firebase-js-sdk/docs-devsite/database.queryconstraint.md

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QueryConstraint class

A QueryConstraint is used to narrow the set of documents returned by a Database query. QueryConstraints are created by invoking endAt(), endBefore(), startAt(), startAfter(), limitToFirst(), limitToLast(), orderByChild(), orderByChild(), orderByKey() , orderByPriority() , orderByValue() or equalTo() and can then be passed to query() to create a new query instance that also contains this QueryConstraint.

Signature:

export declare abstract class QueryConstraint 

Properties

Property	Modifiers	Type	Description
type		QueryConstraintType	The type of this query constraints

QueryConstraint.type

The type of this query constraints

Signature:

abstract readonly type: QueryConstraintType;