feat(firestore): add isType expression (#9484)

.changeset/tiny-jokes-compete.md

@@ -0,0 +1,6 @@
+---
+'firebase': minor
+'@firebase/firestore': minor
+---
+
+feat(firestore): Support added for the `isType` Pipeline expression.

common/api-review/firestore-lite-pipelines.api.md

@@ -502,6 +502,8 @@ export abstract class Expression {
     /* Excluded from this release type: _readUserData */
     isError(): BooleanExpression;
     /* Excluded from this release type: _readUserData */
+    isType(type: Type): BooleanExpression;
+    /* Excluded from this release type: _readUserData */
     join(delimiterExpression: Expression): Expression;
     /* Excluded from this release type: _readUserData */
     join(delimiter: string): Expression;
@@ -771,6 +773,12 @@ export function isAbsent(field: string): BooleanExpression;
 // @beta
 export function isError(value: Expression): BooleanExpression;
 
+// @beta
+export function isType(fieldName: string, type: Type): BooleanExpression;
+
+// @beta
+export function isType(expression: Expression, type: Type): BooleanExpression;
+
 // @beta
 export function join(arrayFieldName: string, delimiter: string): Expression;
 
@@ -1376,6 +1384,9 @@ export function trunc(fieldName: string, decimalPlaces: number | Expression): Fu
 // @beta
 export function trunc(expression: Expression, decimalPlaces: number | Expression): FunctionExpression;
 
+// @beta
+export type Type = 'null' | 'array' | 'boolean' | 'bytes' | 'timestamp' | 'geo_point' | 'number' | 'int32' | 'int64' | 'float64' | 'decimal128' | 'map' | 'reference' | 'string' | 'vector' | 'max_key' | 'min_key' | 'object_id' | 'regex' | 'request_timestamp';
+
 // @beta
 export function type(fieldName: string): FunctionExpression;
 

common/api-review/firestore-pipelines.api.md

@@ -505,6 +505,8 @@ export abstract class Expression {
     /* Excluded from this release type: _readUserData */
     isError(): BooleanExpression;
     /* Excluded from this release type: _readUserData */
+    isType(type: Type): BooleanExpression;
+    /* Excluded from this release type: _readUserData */
     join(delimiterExpression: Expression): Expression;
     /* Excluded from this release type: _readUserData */
     join(delimiter: string): Expression;
@@ -774,6 +776,12 @@ export function isAbsent(field: string): BooleanExpression;
 // @beta
 export function isError(value: Expression): BooleanExpression;
 
+// @beta
+export function isType(fieldName: string, type: Type): BooleanExpression;
+
+// @beta
+export function isType(expression: Expression, type: Type): BooleanExpression;
+
 // @beta
 export function join(arrayFieldName: string, delimiter: string): Expression;
 
@@ -1413,6 +1421,9 @@ export function trunc(fieldName: string, decimalPlaces: number | Expression): Fu
 // @beta
 export function trunc(expression: Expression, decimalPlaces: number | Expression): FunctionExpression;
 
+// @beta
+export type Type = 'null' | 'array' | 'boolean' | 'bytes' | 'timestamp' | 'geo_point' | 'number' | 'int32' | 'int64' | 'float64' | 'decimal128' | 'map' | 'reference' | 'string' | 'vector' | 'max_key' | 'min_key' | 'object_id' | 'regex' | 'request_timestamp';
+
 // @beta
 export function type(fieldName: string): FunctionExpression;
 

docs-devsite/firestore_lite_pipelines.expression.md

@@ -101,6 +101,7 @@ field("optional_field").ifAbsent(field('default_field'))
 |  [ifError(catchValue)](./firestore_lite_pipelines.expression.md#expressioniferror) |  | <b><i>(Public Preview)</i></b> Creates an expression that returns the <code>catch</code> argument if there is an error, else return the result of this expression. |
 |  [isAbsent()](./firestore_lite_pipelines.expression.md#expressionisabsent) |  | <b><i>(Public Preview)</i></b> Creates an expression that returns <code>true</code> if the result of this expression is absent. Otherwise, returns <code>false</code> even if the value is <code>null</code>. |
 |  [isError()](./firestore_lite_pipelines.expression.md#expressioniserror) |  | <b><i>(Public Preview)</i></b> Creates an expression that checks if a given expression produces an error. |
+|  [isType(type)](./firestore_lite_pipelines.expression.md#expressionistype) |  | <b><i>(Public Preview)</i></b> Creates an expression that checks if the result of this expression is of the given type. |
 |  [join(delimiterExpression)](./firestore_lite_pipelines.expression.md#expressionjoin) |  | <b><i>(Public Preview)</i></b> Creates an expression that joins the elements of an array into a string. |
 |  [join(delimiter)](./firestore_lite_pipelines.expression.md#expressionjoin) |  | <b><i>(Public Preview)</i></b> Creates an expression that joins the elements of an array field into a string. |
 |  [last()](./firestore_lite_pipelines.expression.md#expressionlast) |  | <b><i>(Public Preview)</i></b> Creates an aggregation that finds the last value of an expression across multiple stage inputs. |
@@ -1977,6 +1978,42 @@ field("title").arrayContains(1).isError();
 
 ```
 
+## Expression.isType()
+
+> This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
+> 
+
+Creates an expression that checks if the result of this expression is of the given type.
+
+Null or undefined fields evaluate to skip/error. Use `ifAbsent()` / `isAbsent()` to evaluate missing data.
+
+<b>Signature:</b>
+
+```typescript
+isType(type: Type): BooleanExpression;
+```
+
+#### Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  type | [Type](./firestore_lite_pipelines.md#type) | The type to check for. |
+
+<b>Returns:</b>
+
+[BooleanExpression](./firestore_lite_pipelines.booleanexpression.md#booleanexpression_class)
+
+A new `BooleanExpression` that evaluates to true if the expression's result is of the given type, false otherwise.
+
+### Example
+
+
+```typescript
+// Check if the 'price' field is specifically an integer (not just 'number')
+field('price').isType('int64');
+
+```
+
 ## Expression.join()
 
 > This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
@@ -4463,6 +4500,8 @@ field("rating").trunc(constant(2));
 
 Creates an expression that returns the data type of this expression's result, as a string.
 
+This is evaluated on the backend. This means: 1. Generic typed elements (like `array<string>`<!-- -->) evaluate strictly to the primitive `'array'`<!-- -->. 2. Any custom `FirestoreDataConverter` mappings are ignored. 3. For numeric values, the backend does not yield the JavaScript `"number"` type; it evaluates precisely as `"int64"` or `"float64"`<!-- -->. 4. For date or timestamp objects, the backend evaluates to `"timestamp"`<!-- -->.
+
 <b>Signature:</b>
 
 ```typescript

docs-devsite/firestore_lite_pipelines.md

@@ -87,6 +87,7 @@ https://github.com/firebase/firebase-js-sdk
 |  [first(expression)](./firestore_lite_pipelines.md#first_1138a27) | <b><i>(Public Preview)</i></b> Creates an aggregation that finds the first value of an expression across multiple stage inputs. |
 |  [greaterThan(expression, value)](./firestore_lite_pipelines.md#greaterthan_01df3cf) | <b><i>(Public Preview)</i></b> Creates an expression that checks if an expression is greater than a constant value. |
 |  [greaterThanOrEqual(expression, value)](./firestore_lite_pipelines.md#greaterthanorequal_01df3cf) | <b><i>(Public Preview)</i></b> Creates an expression that checks if an expression is greater than or equal to a constant value. |
+|  [isType(expression, type)](./firestore_lite_pipelines.md#istype_27398ce) | <b><i>(Public Preview)</i></b> Creates an expression that checks if the result of an expression is of the given type. |
 |  [last(expression)](./firestore_lite_pipelines.md#last_1138a27) | <b><i>(Public Preview)</i></b> Creates an aggregation that finds the last value of an expression across multiple stage inputs. |
 |  [length\_2(expression)](./firestore_lite_pipelines.md#length_2_1138a27) | <b><i>(Public Preview)</i></b> Creates an expression that calculates the length of a string, array, map, vector, or bytes. |
 |  [lessThan(expression, value)](./firestore_lite_pipelines.md#lessthan_01df3cf) | <b><i>(Public Preview)</i></b> Creates an expression that checks if an expression is less than a constant value. |
@@ -165,6 +166,7 @@ https://github.com/firebase/firebase-js-sdk
 |  [greaterThan(fieldName, value)](./firestore_lite_pipelines.md#greaterthan_65e2f32) | <b><i>(Public Preview)</i></b> Creates an expression that checks if a field's value is greater than a constant value. |
 |  [greaterThanOrEqual(fieldName, value)](./firestore_lite_pipelines.md#greaterthanorequal_2e16acb) | <b><i>(Public Preview)</i></b> Creates an expression that checks if a field's value is greater than or equal to an expression. |
 |  [greaterThanOrEqual(fieldName, value)](./firestore_lite_pipelines.md#greaterthanorequal_65e2f32) | <b><i>(Public Preview)</i></b> Creates an expression that checks if a field's value is greater than or equal to a constant value. |
+|  [isType(fieldName, type)](./firestore_lite_pipelines.md#istype_5da287e) | <b><i>(Public Preview)</i></b> Creates an expression that checks if the value in the specified field is of the given type. |
 |  [last(fieldName)](./firestore_lite_pipelines.md#last_e5b0480) | <b><i>(Public Preview)</i></b> Creates an aggregation that finds the last value of a field across multiple stage inputs. |
 |  [length\_2(fieldName)](./firestore_lite_pipelines.md#length_2_e5b0480) | <b><i>(Public Preview)</i></b> Creates an expression that calculates the length of a string, array, map, vector, or bytes. |
 |  [lessThan(fieldName, expression)](./firestore_lite_pipelines.md#lessthan_1e91657) | <b><i>(Public Preview)</i></b> Creates an expression that checks if a field's value is less than an expression. |
@@ -405,6 +407,7 @@ https://github.com/firebase/firebase-js-sdk
 |  [SetOptions](./firestore_lite_pipelines.md#setoptions) | An options object that configures the behavior of [setDoc()](./firestore_lite.md#setdoc_ee215ad)<!-- -->,  and  calls. These calls can be configured to perform granular merges instead of overwriting the target documents in their entirety by providing a <code>SetOptions</code> with <code>merge: true</code>. |
 |  [SortStageOptions](./firestore_lite_pipelines.md#sortstageoptions) | <b><i>(Public Preview)</i></b> Options defining how a SortStage is evaluated. See [Pipeline.sort()](./firestore_pipelines.pipeline.md#pipelinesort)<!-- -->. |
 |  [TimeGranularity](./firestore_lite_pipelines.md#timegranularity) | <b><i>(Public Preview)</i></b> Specify time granularity for expressions. |
+|  [Type](./firestore_lite_pipelines.md#type) | <b><i>(Public Preview)</i></b> An enumeration of the different types generated by the Firestore backend.<ul> <li>Numerics evaluate directly to backend representation (<code>int64</code> or <code>float64</code>), not JS <code>number</code>.</li> <li>JavaScript <code>Date</code> and firestore <code>Timestamp</code> objects strictly evaluate to <code>'timestamp'</code>.</li> <li>Advanced configurations parsing backend types (such as <code>decimal128</code>, <code>max_key</code> or <code>min_key</code> from BSON) are also incorporated in this union string type. Note that <code>decimal128</code> is a backend-only numeric type that the JavaScript SDK cannot create natively, but can be evaluated in pipelines.</li> </ul> |
 |  [UnionStageOptions](./firestore_lite_pipelines.md#unionstageoptions) | <b><i>(Public Preview)</i></b> Options defining how a UnionStage is evaluated. See [Pipeline.union()](./firestore_pipelines.pipeline.md#pipelineunion)<!-- -->. |
 |  [UnnestStageOptions](./firestore_lite_pipelines.md#unneststageoptions) | <b><i>(Public Preview)</i></b> Represents the specific options available for configuring an <code>UnnestStage</code> within a pipeline. |
 |  [WhereStageOptions](./firestore_lite_pipelines.md#wherestageoptions) | <b><i>(Public Preview)</i></b> Options defining how a WhereStage is evaluated. See [Pipeline.where()](./firestore_pipelines.pipeline.md#pipelinewhere)<!-- -->. |
@@ -2399,6 +2402,43 @@ greaterThanOrEqual(field("quantity"), 10);
 
 ```
 
+### isType(expression, type) {:#istype_27398ce}
+
+> This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
+> 
+
+Creates an expression that checks if the result of an expression is of the given type.
+
+Null or undefined fields evaluate to skip/error. Use `ifAbsent()` / `isAbsent()` to evaluate missing data.
+
+<b>Signature:</b>
+
+```typescript
+export declare function isType(expression: Expression, type: Type): BooleanExpression;
+```
+
+#### Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  expression | [Expression](./firestore_lite_pipelines.expression.md#expression_class) | The expression to check. |
+|  type | [Type](./firestore_lite_pipelines.md#type) | The type to check for. |
+
+<b>Returns:</b>
+
+[BooleanExpression](./firestore_lite_pipelines.booleanexpression.md#booleanexpression_class)
+
+A new `BooleanExpression` that evaluates to true if the expression's result is of the given type, false otherwise.
+
+### Example
+
+
+```typescript
+// Check if the result of a calculation is a number
+isType(add('count', 1), 'number')
+
+```
+
 ### last(expression) {:#last_1138a27}
 
 > This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
@@ -5014,6 +5054,43 @@ greaterThanOrEqual("score", 80);
 
 ```
 
+### isType(fieldName, type) {:#istype_5da287e}
+
+> This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
+> 
+
+Creates an expression that checks if the value in the specified field is of the given type.
+
+Null or undefined fields evaluate to skip/error. Use `ifAbsent()` / `isAbsent()` to evaluate missing data.
+
+<b>Signature:</b>
+
+```typescript
+export declare function isType(fieldName: string, type: Type): BooleanExpression;
+```
+
+#### Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  fieldName | string | The name of the field to check. |
+|  type | [Type](./firestore_lite_pipelines.md#type) | The type to check for. |
+
+<b>Returns:</b>
+
+[BooleanExpression](./firestore_lite_pipelines.booleanexpression.md#booleanexpression_class)
+
+A new `BooleanExpression` that evaluates to true if the field's value is of the given type, false otherwise.
+
+### Example
+
+
+```typescript
+// Check if the 'price' field is a floating point number (evaluating to true inside pipeline conditionals)
+isType('price', 'float64');
+
+```
+
 ### last(fieldName) {:#last_e5b0480}
 
 > This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
@@ -7242,6 +7319,8 @@ trunc("rating", 2);
 
 Creates an expression that returns the data type of the data in the specified field.
 
+String inputs passed iteratively to this global function act as `field()` path lookups. If you wish to pass a string literal value, it must be wrapped: `type(constant("my_string"))`<!-- -->.
+
 <b>Signature:</b>
 
 ```typescript
@@ -10728,6 +10807,21 @@ Specify time granularity for expressions.
 export declare type TimeGranularity = 'microsecond' | 'millisecond' | 'second' | 'minute' | 'hour' | 'day' | 'week' | 'week(monday)' | 'week(tuesday)' | 'week(wednesday)' | 'week(thursday)' | 'week(friday)' | 'week(saturday)' | 'week(sunday)' | 'isoWeek' | 'month' | 'quarter' | 'year' | 'isoYear';
 ```
 
+## Type
+
+> This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
+> 
+
+An enumeration of the different types generated by the Firestore backend.
+
+<ul> <li>Numerics evaluate directly to backend representation (`int64` or `float64`<!-- -->), not JS `number`<!-- -->.</li> <li>JavaScript `Date` and firestore `Timestamp` objects strictly evaluate to `'timestamp'`<!-- -->.</li> <li>Advanced configurations parsing backend types (such as `decimal128`<!-- -->, `max_key` or `min_key` from BSON) are also incorporated in this union string type. Note that `decimal128` is a backend-only numeric type that the JavaScript SDK cannot create natively, but can be evaluated in pipelines.</li> </ul>
+
+<b>Signature:</b>
+
+```typescript
+export declare type Type = 'null' | 'array' | 'boolean' | 'bytes' | 'timestamp' | 'geo_point' | 'number' | 'int32' | 'int64' | 'float64' | 'decimal128' | 'map' | 'reference' | 'string' | 'vector' | 'max_key' | 'min_key' | 'object_id' | 'regex' | 'request_timestamp';
+```
+
 ## UnionStageOptions
 
 > This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.

docs-devsite/firestore_pipelines.expression.md

@@ -101,6 +101,7 @@ field("optional_field").ifAbsent(field('default_field'))
 |  [ifError(catchValue)](./firestore_pipelines.expression.md#expressioniferror) |  | <b><i>(Public Preview)</i></b> Creates an expression that returns the <code>catch</code> argument if there is an error, else return the result of this expression. |
 |  [isAbsent()](./firestore_pipelines.expression.md#expressionisabsent) |  | <b><i>(Public Preview)</i></b> Creates an expression that returns <code>true</code> if the result of this expression is absent. Otherwise, returns <code>false</code> even if the value is <code>null</code>. |
 |  [isError()](./firestore_pipelines.expression.md#expressioniserror) |  | <b><i>(Public Preview)</i></b> Creates an expression that checks if a given expression produces an error. |
+|  [isType(type)](./firestore_pipelines.expression.md#expressionistype) |  | <b><i>(Public Preview)</i></b> Creates an expression that checks if the result of this expression is of the given type. |
 |  [join(delimiterExpression)](./firestore_pipelines.expression.md#expressionjoin) |  | <b><i>(Public Preview)</i></b> Creates an expression that joins the elements of an array into a string. |
 |  [join(delimiter)](./firestore_pipelines.expression.md#expressionjoin) |  | <b><i>(Public Preview)</i></b> Creates an expression that joins the elements of an array field into a string. |
 |  [last()](./firestore_pipelines.expression.md#expressionlast) |  | <b><i>(Public Preview)</i></b> Creates an aggregation that finds the last value of an expression across multiple stage inputs. |
@@ -1977,6 +1978,42 @@ field("title").arrayContains(1).isError();
 
 ```
 
+## Expression.isType()
+
+> This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
+> 
+
+Creates an expression that checks if the result of this expression is of the given type.
+
+Null or undefined fields evaluate to skip/error. Use `ifAbsent()` / `isAbsent()` to evaluate missing data.
+
+<b>Signature:</b>
+
+```typescript
+isType(type: Type): BooleanExpression;
+```
+
+#### Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  type | [Type](./firestore_pipelines.md#type) | The type to check for. |
+
+<b>Returns:</b>
+
+[BooleanExpression](./firestore_pipelines.booleanexpression.md#booleanexpression_class)
+
+A new `BooleanExpression` that evaluates to true if the expression's result is of the given type, false otherwise.
+
+### Example
+
+
+```typescript
+// Check if the 'price' field is specifically an integer (not just 'number')
+field('price').isType('int64');
+
+```
+
 ## Expression.join()
 
 > This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
@@ -4463,6 +4500,8 @@ field("rating").trunc(constant(2));
 
 Creates an expression that returns the data type of this expression's result, as a string.
 
+This is evaluated on the backend. This means: 1. Generic typed elements (like `array<string>`<!-- -->) evaluate strictly to the primitive `'array'`<!-- -->. 2. Any custom `FirestoreDataConverter` mappings are ignored. 3. For numeric values, the backend does not yield the JavaScript `"number"` type; it evaluates precisely as `"int64"` or `"float64"`<!-- -->. 4. For date or timestamp objects, the backend evaluates to `"timestamp"`<!-- -->.
+
 <b>Signature:</b>
 
 ```typescript

docs-devsite/firestore_pipelines.md

@@ -87,6 +87,7 @@ https://github.com/firebase/firebase-js-sdk
 |  [first(expression)](./firestore_pipelines.md#first_1138a27) | <b><i>(Public Preview)</i></b> Creates an aggregation that finds the first value of an expression across multiple stage inputs. |
 |  [greaterThan(expression, value)](./firestore_pipelines.md#greaterthan_01df3cf) | <b><i>(Public Preview)</i></b> Creates an expression that checks if an expression is greater than a constant value. |
 |  [greaterThanOrEqual(expression, value)](./firestore_pipelines.md#greaterthanorequal_01df3cf) | <b><i>(Public Preview)</i></b> Creates an expression that checks if an expression is greater than or equal to a constant value. |
+|  [isType(expression, type)](./firestore_pipelines.md#istype_27398ce) | <b><i>(Public Preview)</i></b> Creates an expression that checks if the result of an expression is of the given type. |
 |  [last(expression)](./firestore_pipelines.md#last_1138a27) | <b><i>(Public Preview)</i></b> Creates an aggregation that finds the last value of an expression across multiple stage inputs. |
 |  [length\_2(expression)](./firestore_pipelines.md#length_2_1138a27) | <b><i>(Public Preview)</i></b> Creates an expression that calculates the length of a string, array, map, vector, or bytes. |
 |  [lessThan(expression, value)](./firestore_pipelines.md#lessthan_01df3cf) | <b><i>(Public Preview)</i></b> Creates an expression that checks if an expression is less than a constant value. |
@@ -165,6 +166,7 @@ https://github.com/firebase/firebase-js-sdk
 |  [greaterThan(fieldName, value)](./firestore_pipelines.md#greaterthan_65e2f32) | <b><i>(Public Preview)</i></b> Creates an expression that checks if a field's value is greater than a constant value. |
 |  [greaterThanOrEqual(fieldName, value)](./firestore_pipelines.md#greaterthanorequal_2e16acb) | <b><i>(Public Preview)</i></b> Creates an expression that checks if a field's value is greater than or equal to an expression. |
 |  [greaterThanOrEqual(fieldName, value)](./firestore_pipelines.md#greaterthanorequal_65e2f32) | <b><i>(Public Preview)</i></b> Creates an expression that checks if a field's value is greater than or equal to a constant value. |
+|  [isType(fieldName, type)](./firestore_pipelines.md#istype_5da287e) | <b><i>(Public Preview)</i></b> Creates an expression that checks if the value in the specified field is of the given type. |
 |  [last(fieldName)](./firestore_pipelines.md#last_e5b0480) | <b><i>(Public Preview)</i></b> Creates an aggregation that finds the last value of a field across multiple stage inputs. |
 |  [length\_2(fieldName)](./firestore_pipelines.md#length_2_e5b0480) | <b><i>(Public Preview)</i></b> Creates an expression that calculates the length of a string, array, map, vector, or bytes. |
 |  [lessThan(fieldName, expression)](./firestore_pipelines.md#lessthan_1e91657) | <b><i>(Public Preview)</i></b> Creates an expression that checks if a field's value is less than an expression. |
@@ -411,6 +413,7 @@ https://github.com/firebase/firebase-js-sdk
 |  [SetOptions](./firestore_pipelines.md#setoptions) | An options object that configures the behavior of [setDoc()](./firestore_lite.md#setdoc_ee215ad)<!-- -->,  and  calls. These calls can be configured to perform granular merges instead of overwriting the target documents in their entirety by providing a <code>SetOptions</code> with <code>merge: true</code>. |
 |  [SortStageOptions](./firestore_pipelines.md#sortstageoptions) | <b><i>(Public Preview)</i></b> Options defining how a SortStage is evaluated. See [Pipeline.sort()](./firestore_pipelines.pipeline.md#pipelinesort)<!-- -->. |
 |  [TimeGranularity](./firestore_pipelines.md#timegranularity) | <b><i>(Public Preview)</i></b> Specify time granularity for expressions. |
+|  [Type](./firestore_pipelines.md#type) | <b><i>(Public Preview)</i></b> An enumeration of the different types generated by the Firestore backend.<ul> <li>Numerics evaluate directly to backend representation (<code>int64</code> or <code>float64</code>), not JS <code>number</code>.</li> <li>JavaScript <code>Date</code> and firestore <code>Timestamp</code> objects strictly evaluate to <code>'timestamp'</code>.</li> <li>Advanced configurations parsing backend types (such as <code>decimal128</code>, <code>max_key</code> or <code>min_key</code> from BSON) are also incorporated in this union string type. Note that <code>decimal128</code> is a backend-only numeric type that the JavaScript SDK cannot create natively, but can be evaluated in pipelines.</li> </ul> |
 |  [UnionStageOptions](./firestore_pipelines.md#unionstageoptions) | <b><i>(Public Preview)</i></b> Options defining how a UnionStage is evaluated. See [Pipeline.union()](./firestore_pipelines.pipeline.md#pipelineunion)<!-- -->. |
 |  [UnnestStageOptions](./firestore_pipelines.md#unneststageoptions) | <b><i>(Public Preview)</i></b> Represents the specific options available for configuring an <code>UnnestStage</code> within a pipeline. |
 |  [WhereStageOptions](./firestore_pipelines.md#wherestageoptions) | <b><i>(Public Preview)</i></b> Options defining how a WhereStage is evaluated. See [Pipeline.where()](./firestore_pipelines.pipeline.md#pipelinewhere)<!-- -->. |
@@ -2405,6 +2408,43 @@ greaterThanOrEqual(field("quantity"), 10);
 
 ```
 
+### isType(expression, type) {:#istype_27398ce}
+
+> This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
+> 
+
+Creates an expression that checks if the result of an expression is of the given type.
+
+Null or undefined fields evaluate to skip/error. Use `ifAbsent()` / `isAbsent()` to evaluate missing data.
+
+<b>Signature:</b>
+
+```typescript
+export declare function isType(expression: Expression, type: Type): BooleanExpression;
+```
+
+#### Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  expression | [Expression](./firestore_pipelines.expression.md#expression_class) | The expression to check. |
+|  type | [Type](./firestore_pipelines.md#type) | The type to check for. |
+
+<b>Returns:</b>
+
+[BooleanExpression](./firestore_pipelines.booleanexpression.md#booleanexpression_class)
+
+A new `BooleanExpression` that evaluates to true if the expression's result is of the given type, false otherwise.
+
+### Example
+
+
+```typescript
+// Check if the result of a calculation is a number
+isType(add('count', 1), 'number')
+
+```
+
 ### last(expression) {:#last_1138a27}
 
 > This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
@@ -5020,6 +5060,43 @@ greaterThanOrEqual("score", 80);
 
 ```
 
+### isType(fieldName, type) {:#istype_5da287e}
+
+> This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
+> 
+
+Creates an expression that checks if the value in the specified field is of the given type.
+
+Null or undefined fields evaluate to skip/error. Use `ifAbsent()` / `isAbsent()` to evaluate missing data.
+
+<b>Signature:</b>
+
+```typescript
+export declare function isType(fieldName: string, type: Type): BooleanExpression;
+```
+
+#### Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  fieldName | string | The name of the field to check. |
+|  type | [Type](./firestore_pipelines.md#type) | The type to check for. |
+
+<b>Returns:</b>
+
+[BooleanExpression](./firestore_pipelines.booleanexpression.md#booleanexpression_class)
+
+A new `BooleanExpression` that evaluates to true if the field's value is of the given type, false otherwise.
+
+### Example
+
+
+```typescript
+// Check if the 'price' field is a floating point number (evaluating to true inside pipeline conditionals)
+isType('price', 'float64');
+
+```
+
 ### last(fieldName) {:#last_e5b0480}
 
 > This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
@@ -7248,6 +7325,8 @@ trunc("rating", 2);
 
 Creates an expression that returns the data type of the data in the specified field.
 
+String inputs passed iteratively to this global function act as `field()` path lookups. If you wish to pass a string literal value, it must be wrapped: `type(constant("my_string"))`<!-- -->.
+
 <b>Signature:</b>
 
 ```typescript
@@ -10803,6 +10882,21 @@ Specify time granularity for expressions.
 export declare type TimeGranularity = 'microsecond' | 'millisecond' | 'second' | 'minute' | 'hour' | 'day' | 'week' | 'week(monday)' | 'week(tuesday)' | 'week(wednesday)' | 'week(thursday)' | 'week(friday)' | 'week(saturday)' | 'week(sunday)' | 'isoWeek' | 'month' | 'quarter' | 'year' | 'isoYear';
 ```
 
+## Type
+
+> This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
+> 
+
+An enumeration of the different types generated by the Firestore backend.
+
+<ul> <li>Numerics evaluate directly to backend representation (`int64` or `float64`<!-- -->), not JS `number`<!-- -->.</li> <li>JavaScript `Date` and firestore `Timestamp` objects strictly evaluate to `'timestamp'`<!-- -->.</li> <li>Advanced configurations parsing backend types (such as `decimal128`<!-- -->, `max_key` or `min_key` from BSON) are also incorporated in this union string type. Note that `decimal128` is a backend-only numeric type that the JavaScript SDK cannot create natively, but can be evaluated in pipelines.</li> </ul>
+
+<b>Signature:</b>
+
+```typescript
+export declare type Type = 'null' | 'array' | 'boolean' | 'bytes' | 'timestamp' | 'geo_point' | 'number' | 'int32' | 'int64' | 'float64' | 'decimal128' | 'map' | 'reference' | 'string' | 'vector' | 'max_key' | 'min_key' | 'object_id' | 'regex' | 'request_timestamp';
+```
+
 ## UnionStageOptions
 
 > This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.

packages/firestore/lite/pipelines/pipelines.ts

@@ -141,6 +141,8 @@ export {
   trim,
   ltrim,
   rtrim,
+  type,
+  isType,
   stringConcat,
   stringIndexOf,
   stringRepeat,
@@ -193,7 +195,6 @@ export {
   arraySum,
   split,
   timestampTruncate,
-  type,
   AliasedExpression,
   Field,
   Constant,
@@ -204,5 +205,6 @@ export {
   Selectable,
   BooleanExpression,
   AggregateFunction,
-  TimeGranularity
+  TimeGranularity,
+  Type
 } from '../../src/lite-api/expressions';

packages/firestore/src/api_pipelines.ts

@@ -96,6 +96,8 @@ export {
   trim,
   ltrim,
   rtrim,
+  type,
+  isType,
   stringConcat,
   stringIndexOf,
   stringRepeat,
@@ -162,7 +164,6 @@ export {
   arraySum,
   timestampTruncate,
   split,
-  type,
   Expression,
   AliasedExpression,
   Field,
@@ -173,7 +174,8 @@ export {
   ExpressionType,
   AliasedAggregate,
   Selectable,
-  TimeGranularity
+  TimeGranularity,
+  Type
 } from './lite-api/expressions';
 
 export { _internalPipelineToExecutePipelineRequestProto } from './remote/internal_serializer';

packages/firestore/src/lite-api/expressions.ts

@@ -55,6 +55,39 @@ export type ExpressionType =
   | 'ListOfExpressions'
   | 'AliasedExpression';
 
+/**
+ * @beta
+ *
+ * An enumeration of the different types generated by the Firestore backend.
+ *
+ * <ul>
+ *  <li>Numerics evaluate directly to backend representation (`int64` or `float64`), not JS `number`.</li>
+ *  <li>JavaScript `Date` and firestore `Timestamp` objects strictly evaluate to `'timestamp'`.</li>
+ *  <li>Advanced configurations parsing backend types (such as `decimal128`, `max_key` or `min_key` from BSON) are also incorporated in this union string type. Note that `decimal128` is a backend-only numeric type that the JavaScript SDK cannot create natively, but can be evaluated in pipelines.</li>
+ * </ul>
+ */
+export type Type =
+  | 'null'
+  | 'array'
+  | 'boolean'
+  | 'bytes'
+  | 'timestamp'
+  | 'geo_point'
+  | 'number'
+  | 'int32'
+  | 'int64'
+  | 'float64'
+  | 'decimal128'
+  | 'map'
+  | 'reference'
+  | 'string'
+  | 'vector'
+  | 'max_key'
+  | 'min_key'
+  | 'object_id'
+  | 'regex'
+  | 'request_timestamp';
+
 /**
  * Converts a value to an Expression, Returning either a Constant, MapFunction,
  * ArrayFunction, or the input itself (if it's already an expression).
@@ -1266,6 +1299,53 @@ export abstract class Expression implements ProtoValueSerializable, UserData {
     return new FunctionExpression('rtrim', args, 'rtrim');
   }
 
+  /**
+   * @beta
+   * Creates an expression that returns the data type of this expression's result, as a string.
+   *
+   * @remarks
+   * This is evaluated on the backend. This means:
+   * 1. Generic typed elements (like `array<string>`) evaluate strictly to the primitive `'array'`.
+   * 2. Any custom `FirestoreDataConverter` mappings are ignored.
+   * 3. For numeric values, the backend does not yield the JavaScript `"number"` type; it evaluates
+   *    precisely as `"int64"` or `"float64"`.
+   * 4. For date or timestamp objects, the backend evaluates to `"timestamp"`.
+   *
+   * @example
+   * ```typescript
+   * // Get the data type of the value in field 'title'
+   * field('title').type()
+   * ```
+   *
+   * @returns A new `Expression` representing the data type.
+   */
+  type(): FunctionExpression {
+    return new FunctionExpression('type', [this]);
+  }
+
+  /**
+   * @beta
+   * Creates an expression that checks if the result of this expression is of the given type.
+   *
+   * @remarks Null or undefined fields evaluate to skip/error. Use `ifAbsent()` / `isAbsent()` to evaluate missing data.
+   *
+   * @example
+   * ```typescript
+   * // Check if the 'price' field is specifically an integer (not just 'number')
+   * field('price').isType('int64');
+   * ```
+   *
+   * @param type - The type to check for.
+   * @returns A new `BooleanExpression` that evaluates to true if the expression's result is of the given type, false otherwise.
+   */
+  isType(type: Type): BooleanExpression {
+    return new FunctionExpression(
+      'is_type',
+      [this, constant(type)],
+      'isType'
+    ).asBoolean();
+  }
+
   /**
    * @beta
    * Creates an expression that concatenates string expressions together.
@@ -2791,22 +2871,6 @@ export abstract class Expression implements ProtoValueSerializable, UserData {
     return new FunctionExpression('timestamp_trunc', args);
   }
 
-  /**
-   * @beta
-   * Creates an expression that returns the data type of this expression's result, as a string.
-   *
-   * @example
-   * ```typescript
-   * // Get the data type of the value in field 'title'
-   * field('title').type()
-   * ```
-   *
-   * @returns A new `Expression` representing the data type.
-   */
-  type(): FunctionExpression {
-    return new FunctionExpression('type', [this]);
-  }
-
   // TODO(new-expression): Add new expression method definitions above this line
 
   /**
@@ -7056,6 +7120,84 @@ export function rtrim(
   return fieldOrExpression(expr).rtrim(valueToTrim);
 }
 
+/**
+ * @beta
+ * Creates an expression that returns the data type of the data in the specified field.
+ *
+ * @remarks
+ * String inputs passed iteratively to this global function act as `field()` path lookups.
+ * If you wish to pass a string literal value, it must be wrapped: `type(constant("my_string"))`.
+ *
+ * @example
+ * ```typescript
+ * // Get the data type of the value in field 'title'
+ * type('title')
+ * ```
+ *
+ * @returns A new `Expression` representing the data type.
+ */
+export function type(fieldName: string): FunctionExpression;
+/**
+ * @beta
+ * Creates an expression that returns the data type of an expression's result.
+ *
+ * @example
+ * ```typescript
+ * // Get the data type of a conditional expression
+ * type(conditional(exists('foo'), constant(1), constant(true)))
+ * ```
+ *
+ * @returns A new `Expression` representing the data type.
+ */
+export function type(expression: Expression): FunctionExpression;
+export function type(
+  fieldNameOrExpression: string | Expression
+): FunctionExpression {
+  return fieldOrExpression(fieldNameOrExpression).type();
+}
+
+/**
+ * @beta
+ * Creates an expression that checks if the value in the specified field is of the given type.
+ *
+ * @remarks Null or undefined fields evaluate to skip/error. Use `ifAbsent()` / `isAbsent()` to evaluate missing data.
+ *
+ * @example
+ * ```typescript
+ * // Check if the 'price' field is a floating point number (evaluating to true inside pipeline conditionals)
+ * isType('price', 'float64');
+ * ```
+ *
+ * @param fieldName - The name of the field to check.
+ * @param type - The type to check for.
+ * @returns A new `BooleanExpression` that evaluates to true if the field's value is of the given type, false otherwise.
+ */
+export function isType(fieldName: string, type: Type): BooleanExpression;
+
+/**
+ * @beta
+ * Creates an expression that checks if the result of an expression is of the given type.
+ *
+ * @remarks Null or undefined fields evaluate to skip/error. Use `ifAbsent()` / `isAbsent()` to evaluate missing data.
+ *
+ * @example
+ * ```typescript
+ * // Check if the result of a calculation is a number
+ * isType(add('count', 1), 'number')
+ * ```
+ *
+ * @param expression - The expression to check.
+ * @param type - The type to check for.
+ * @returns A new `BooleanExpression` that evaluates to true if the expression's result is of the given type, false otherwise.
+ */
+export function isType(expression: Expression, type: Type): BooleanExpression;
+export function isType(
+  fieldNameOrExpression: string | Expression,
+  type: Type
+): BooleanExpression {
+  return fieldOrExpression(fieldNameOrExpression).isType(type);
+}
+
 /**
  * @beta
  *
@@ -9446,38 +9588,6 @@ export function timestampTruncate(
   );
 }
 
-/**
- * @beta
- * Creates an expression that returns the data type of the data in the specified field.
- *
- * @example
- * ```typescript
- * // Get the data type of the value in field 'title'
- * type('title')
- * ```
- *
- * @returns A new `Expression` representing the data type.
- */
-export function type(fieldName: string): FunctionExpression;
-/**
- * @beta
- * Creates an expression that returns the data type of an expression's result.
- *
- * @example
- * ```typescript
- * // Get the data type of a conditional expression
- * type(conditional(exists('foo'), constant(1), constant(true)))
- * ```
- *
- * @returns A new `Expression` representing the data type.
- */
-export function type(expression: Expression): FunctionExpression;
-export function type(
-  fieldNameOrExpression: string | Expression
-): FunctionExpression {
-  return fieldOrExpression(fieldNameOrExpression).type();
-}
-
 // TODO(new-expression): Add new top-level expression function definitions above this line
 
 /**

packages/firestore/test/integration/api/pipeline.test.ts

@@ -154,7 +154,8 @@ import {
   PipelineSnapshot,
   timestampTruncate,
   split,
-  type
+  type,
+  isType
 } from '../util/pipeline_export';
 
 use(chaiAsPromised);
@@ -4507,6 +4508,75 @@ apiDescribe.skipClassic('Pipelines', persistence => {
       });
     });
 
+    it('supports isType', async () => {
+      const result = await execute(
+        firestore
+          .pipeline()
+          .collection(randomCol)
+          .limit(1)
+          .replaceWith(
+            map({
+              int: constant(1),
+              float: constant(1.1),
+              str: constant('a string'),
+              bool: constant(true),
+              null: constant(null),
+              geoPoint: constant(new GeoPoint(0.1, 0.2)),
+              timestamp: constant(new Timestamp(123456, 0)),
+              bytes: constant(Bytes.fromUint8Array(new Uint8Array([1, 2, 3]))),
+              docRef: constant(doc(firestore, randomCol.path, 'bar')),
+              vector: constant(vector([1, 2, 3])),
+              map: map({
+                numberK: 1,
+                stringK: 'a string'
+              }),
+              array: array([1, '2', true])
+            })
+          )
+          .select(
+            isType(field('int'), 'int64').as('isInt64'),
+            isType(field('int'), 'number').as('isInt64IsNumber'),
+            isType(field('int'), 'decimal128').as('isInt64IsDecimal128'),
+            field('float').isType('float64').as('isFloat64'),
+            field('float').isType('number').as('isFloat64IsNumber'),
+            field('float').isType('decimal128').as('isFloat64IsDecimal128'),
+            isType('str', 'string').as('isStr'),
+            isType('int', 'string').as('isNumStr'),
+            field('bool').isType('boolean').as('isBool'),
+            isType('null', 'null').as('isNull'),
+            field('geoPoint').isType('geo_point').as('isGeoPoint'),
+            isType('timestamp', 'timestamp').as('isTimestamp'),
+            field('bytes').isType('bytes').as('isBytes'),
+            isType('docRef', 'reference').as('isDocRef'),
+            field('vector').isType('vector').as('isVector'),
+            isType('map', 'map').as('isMap'),
+            field('array').isType('array').as('isArray'),
+            field('str').isType('int64').as('isStrNum')
+          )
+      );
+
+      expectResults(result, {
+        isInt64: true,
+        isInt64IsNumber: true,
+        isInt64IsDecimal128: false,
+        isFloat64: true,
+        isFloat64IsNumber: true,
+        isFloat64IsDecimal128: false,
+        isStr: true,
+        isNumStr: false,
+        isBool: true,
+        isNull: true,
+        isGeoPoint: true,
+        isTimestamp: true,
+        isBytes: true,
+        isDocRef: true,
+        isVector: true,
+        isMap: true,
+        isArray: true,
+        isStrNum: false
+      });
+    });
+
     // TODO(new-expression): Add new expression tests above this line
   });
 

packages/firestore/test/lite/pipeline.test.ts

@@ -66,6 +66,7 @@ import {
   ifError,
   isAbsent,
   isError,
+  isType,
   or,
   map,
   length,
@@ -134,6 +135,7 @@ import {
   toLower,
   toUpper,
   trim,
+  type,
   byteLength,
   arrayGet,
   abs,
@@ -4125,6 +4127,133 @@ describe.skipClassic('Firestore Pipelines', () => {
         indexOfByte: 1
       });
     });
+    it('testType', async () => {
+      const snapshot = await execute(
+        firestore
+          .pipeline()
+          .collection(randomCol.path)
+          .replaceWith(
+            map({
+              int: constant(1),
+              float: constant(1.1),
+              str: constant('a string'),
+              bool: constant(true),
+              null: constant(null),
+              geoPoint: constant(new GeoPoint(0.1, 0.2)),
+              timestamp: constant(new Timestamp(123456, 0)),
+              bytes: constant(
+                Bytes.fromUint8Array(new Uint8Array([1, 2, 3, 4, 5, 6, 7, 0]))
+              ),
+              docRef: constant(doc(firestore, 'foo', 'bar')),
+              vector: constant(vector([1, 2, 3])),
+              map: map({
+                'number': 1,
+                'string': 'a string'
+              }),
+              list: array([1, '2', true])
+            })
+          )
+          .select(
+            type(field('int')).as('int'),
+            field('float').type().as('float'),
+            type('str').as('str'),
+            field('bool').type().as('bool'),
+            type('null').as('null'),
+            field('geoPoint').type().as('geoPoint'),
+            type('timestamp').as('timestamp'),
+            field('bytes').type().as('bytes'),
+            type('docRef').as('docRef'),
+            field('vector').type().as('vector'),
+            type('map').as('map'),
+            field('list').type().as('list')
+          )
+          .limit(1)
+      );
+
+      expectResults(snapshot, {
+        int: 'int64',
+        float: 'float64',
+        str: 'string',
+        bool: 'boolean',
+        null: 'null',
+        geoPoint: 'geo_point',
+        timestamp: 'timestamp',
+        bytes: 'bytes',
+        docRef: 'reference',
+        vector: 'vector',
+        map: 'map',
+        list: 'array'
+      });
+    });
+
+    it('testIsType', async () => {
+      const snapshot = await execute(
+        firestore
+          .pipeline()
+          .collection(randomCol.path)
+          .replaceWith(
+            map({
+              int: constant(1),
+              float: constant(1.1),
+              str: constant('a string'),
+              bool: constant(true),
+              null: constant(null),
+              geoPoint: constant(new GeoPoint(0.1, 0.2)),
+              timestamp: constant(new Timestamp(123456, 0)),
+              bytes: constant(Bytes.fromUint8Array(new Uint8Array([1, 2, 3]))),
+              docRef: constant(doc(firestore, randomCol.path, 'bar')),
+              vector: constant(vector([1, 2, 3])),
+              map: map({
+                numberK: 1,
+                stringK: 'a string'
+              }),
+              array: array([1, '2', true])
+            })
+          )
+          .select(
+            isType(field('int'), 'int64').as('isInt64'),
+            isType(field('int'), 'number').as('isInt64IsNumber'),
+            isType(field('int'), 'decimal128').as('isInt64IsDecimal128'),
+            field('float').isType('float64').as('isFloat64'),
+            field('float').isType('number').as('isFloat64IsNumber'),
+            field('float').isType('decimal128').as('isFloat64IsDecimal128'),
+            isType('str', 'string').as('isStr'),
+            isType('int', 'string').as('isNumStr'),
+            field('bool').isType('boolean').as('isBool'),
+            isType('null', 'null').as('isNull'),
+            field('geoPoint').isType('geo_point').as('isGeoPoint'),
+            isType('timestamp', 'timestamp').as('isTimestamp'),
+            field('bytes').isType('bytes').as('isBytes'),
+            isType('docRef', 'reference').as('isDocRef'),
+            field('vector').isType('vector').as('isVector'),
+            isType('map', 'map').as('isMap'),
+            field('array').isType('array').as('isArray'),
+            field('str').isType('int64').as('isStrNum')
+          )
+          .limit(1)
+      );
+
+      expectResults(snapshot, {
+        isInt64: true,
+        isInt64IsNumber: true,
+        isInt64IsDecimal128: false,
+        isFloat64: true,
+        isFloat64IsNumber: true,
+        isFloat64IsDecimal128: false,
+        isStr: true,
+        isNumStr: false,
+        isBool: true,
+        isNull: true,
+        isGeoPoint: true,
+        isTimestamp: true,
+        isBytes: true,
+        isDocRef: true,
+        isVector: true,
+        isMap: true,
+        isArray: true,
+        isStrNum: false
+      });
+    });
 
     it('test reverse', async () => {
       const snapshot = await execute(