backport Iterator.prototype.join

packages/core-js-compat/src/data.mjs

@@ -2636,6 +2636,8 @@ export const data = {
   },
   'esnext.iterator.indexed': {
   },
+  'esnext.iterator.join': {
+  },
   // TODO: Remove from `core-js@4`
   'esnext.iterator.map': null,
   'esnext.iterator.range': {

packages/core-js-compat/src/modules-by-versions.mjs

@@ -327,5 +327,6 @@ export default {
     'es.iterator.zip',
     'es.iterator.zip-keyed',
     'esnext.iterator.includes',
+    'esnext.iterator.join',
   ],
 };

packages/core-js/actual/iterator/concat.js

@@ -3,6 +3,7 @@ var parent = require('../../stable/iterator/concat');
 require('../../modules/esnext.iterator.chunks');
 require('../../modules/esnext.iterator.concat');
 require('../../modules/esnext.iterator.includes');
+require('../../modules/esnext.iterator.join');
 require('../../modules/esnext.iterator.windows');
 
 module.exports = parent;

packages/core-js/actual/iterator/from.js

@@ -12,6 +12,7 @@ require('../../modules/esnext.iterator.flat-map');
 require('../../modules/esnext.iterator.for-each');
 require('../../modules/esnext.iterator.from');
 require('../../modules/esnext.iterator.includes');
+require('../../modules/esnext.iterator.join');
 require('../../modules/esnext.iterator.map');
 require('../../modules/esnext.iterator.reduce');
 require('../../modules/esnext.iterator.some');

packages/core-js/actual/iterator/index.js

@@ -14,6 +14,7 @@ require('../../modules/esnext.iterator.flat-map');
 require('../../modules/esnext.iterator.for-each');
 require('../../modules/esnext.iterator.from');
 require('../../modules/esnext.iterator.includes');
+require('../../modules/esnext.iterator.join');
 require('../../modules/esnext.iterator.map');
 require('../../modules/esnext.iterator.reduce');
 require('../../modules/esnext.iterator.some');

packages/core-js/actual/iterator/join.js

@@ -0,0 +1,8 @@
+'use strict';
+require('../../modules/es.object.to-string');
+require('../../modules/es.iterator.constructor');
+require('../../modules/esnext.iterator.join');
+
+var entryUnbind = require('../../internals/entry-unbind');
+
+module.exports = entryUnbind('Iterator', 'join');

packages/core-js/actual/iterator/zip-keyed.js

@@ -2,6 +2,7 @@
 var parent = require('../../stable/iterator/zip');
 require('../../modules/esnext.iterator.chunks');
 require('../../modules/esnext.iterator.includes');
+require('../../modules/esnext.iterator.join');
 require('../../modules/esnext.iterator.windows');
 require('../../modules/esnext.iterator.zip-keyed');
 

packages/core-js/actual/iterator/zip.js

@@ -2,6 +2,7 @@
 var parent = require('../../stable/iterator/zip');
 require('../../modules/esnext.iterator.chunks');
 require('../../modules/esnext.iterator.includes');
+require('../../modules/esnext.iterator.join');
 require('../../modules/esnext.iterator.windows');
 require('../../modules/esnext.iterator.zip');
 

packages/core-js/full/iterator/join.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../actual/iterator/join');
+
+module.exports = parent;

packages/core-js/full/iterator/range.js

@@ -18,6 +18,7 @@ require('../../modules/es.iterator.to-array');
 require('../../modules/esnext.iterator.constructor');
 require('../../modules/esnext.iterator.chunks');
 require('../../modules/esnext.iterator.includes');
+require('../../modules/esnext.iterator.join');
 require('../../modules/esnext.iterator.range');
 require('../../modules/esnext.iterator.sliding');
 require('../../modules/esnext.iterator.windows');

packages/core-js/modules/esnext.iterator.join.js

@@ -0,0 +1,31 @@
+'use strict';
+var $ = require('../internals/export');
+var $toString = require('../internals/to-string');
+var anObject = require('../internals/an-object');
+var isNullOrUndefined = require('../internals/is-null-or-undefined');
+var iterate = require('../internals/iterate');
+var iteratorClose = require('../internals/iterator-close');
+var uncurryThis = require('../internals/function-uncurry-this');
+var IS_PURE = require('../internals/is-pure');
+
+var $join = uncurryThis([].join);
+var push = uncurryThis([].push);
+
+// `Iterator.prototype.join` method
+// https://github.com/tc39/proposal-iterator-join
+$({ target: 'Iterator', proto: true, real: true, forced: IS_PURE }, {
+  join: function join(separator) {
+    anObject(this);
+    var sep;
+    try {
+      sep = separator === undefined ? ',' : $toString(separator);
+    } catch (error) {
+      iteratorClose(this, 'throw', error);
+    }
+    var result = [];
+    iterate(this, function (value) {
+      push(result, isNullOrUndefined(value) ? '' : $toString(value));
+    }, { IS_ITERATOR: true });
+    return $join(result, sep);
+  }
+});

packages/core-js/proposals/iterator-join.js

@@ -0,0 +1,3 @@
+'use strict';
+// https://github.com/tc39/proposal-iterator-join
+require('../modules/esnext.iterator.join');

packages/core-js/stage/3.js

@@ -3,6 +3,7 @@ var parent = require('./4');
 
 require('../proposals/decorator-metadata-v2');
 require('../proposals/iterator-includes');
+require('../proposals/iterator-join');
 require('../proposals/joint-iteration');
 // TODO: Obsolete versions, remove from `core-js@4`
 require('../proposals/array-grouping-stage-3');