validate arguments before opening iterator in iterator helpers

babel/proposals#87 (comment)
tc39/proposal-iterator-helpers#265

Author: zloirock

CHANGELOG.md

@@ -2,6 +2,8 @@
 ##### Unreleased
 - [`Set` methods proposal](https://github.com/tc39/proposal-set-methods):
   - Removed sort from `Set.prototype.intersection`, [March 2023 TC39 meeting](https://github.com/babel/proposals/issues/87#issuecomment-1478610425), [proposal-set-methods/94](https://github.com/tc39/proposal-set-methods/pull/94)
+- (Async) Iterator Helpers proposals ([sync](https://github.com/tc39/proposal-iterator-helpers), [async](https://github.com/tc39/proposal-async-iterator-helpers)):
+  - Validate arguments before opening iterator, [March 2023 TC39 meeting](https://github.com/babel/proposals/issues/87#issuecomment-1478412430), [proposal-iterator-helpers/265](https://github.com/tc39/proposal-iterator-helpers/pull/265)
 - (Async) Explicit Resource Management proposals ([sync](https://github.com/tc39/proposal-explicit-resource-management), [async](https://github.com/tc39/proposal-async-explicit-resource-management)):
   - `(Async)DisposableStack.prototype.move` marks the original stack as disposed, [#1226](https://github.com/zloirock/core-js/issues/1226)
   - Some simplifications like [proposal-explicit-resource-management/150](https://github.com/tc39/proposal-explicit-resource-management/pull/150)

packages/core-js/internals/async-iterator-iteration.js

@@ -16,13 +16,14 @@ var createMethod = function (TYPE) {
   var IS_EVERY = TYPE == 2;
   var IS_SOME = TYPE == 3;
   return function (object, fn, target) {
+    anObject(object);
+    var MAPPING = fn !== undefined;
+    if (MAPPING || !IS_TO_ARRAY) aCallable(fn);
     var record = getIteratorDirect(object);
     var Promise = getBuiltIn('Promise');
     var iterator = record.iterator;
     var next = record.next;
     var counter = 0;
-    var MAPPING = fn !== undefined;
-    if (MAPPING || !IS_TO_ARRAY) aCallable(fn);
 
     return new Promise(function (resolve, reject) {
       var ifAbruptCloseAsyncIterator = function (error) {

packages/core-js/internals/async-iterator-map.js

@@ -49,7 +49,9 @@ var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise) {
 // `AsyncIterator.prototype.map` method
 // https://github.com/tc39/proposal-iterator-helpers
 module.exports = function map(mapper) {
+  anObject(this);
+  aCallable(mapper);
   return new AsyncIteratorProxy(getIteratorDirect(this), {
-    mapper: aCallable(mapper)
+    mapper: mapper
   });
 };

packages/core-js/internals/get-async-iterator-flattenable.js

@@ -18,7 +18,7 @@ module.exports = function from(obj) {
     method = getIteratorMethod(object);
     alreadyAsync = false;
   }
-  if (isCallable(method)) {
+  if (method !== undefined) {
     iterator = call(method, object);
   } else {
     iterator = object;

packages/core-js/internals/get-iterator-direct.js

@@ -1,9 +1,8 @@
 var aCallable = require('../internals/a-callable');
-var anObject = require('../internals/an-object');
 
 module.exports = function (obj) {
   return {
     iterator: obj,
-    next: aCallable(anObject(obj).next)
+    next: aCallable(obj.next)
   };
 };

packages/core-js/internals/get-iterator-flattenable.js

@@ -1,11 +1,10 @@
 var call = require('../internals/function-call');
-var isCallable = require('../internals/is-callable');
 var anObject = require('../internals/an-object');
 var getIteratorDirect = require('../internals/get-iterator-direct');
 var getIteratorMethod = require('../internals/get-iterator-method');
 
 module.exports = function (obj) {
   var object = anObject(obj);
   var method = getIteratorMethod(object);
-  return getIteratorDirect(anObject(isCallable(method) ? call(method, object) : object));
+  return getIteratorDirect(anObject(method !== undefined ? call(method, object) : object));
 };

packages/core-js/internals/iterator-map.js

@@ -16,7 +16,9 @@ var IteratorProxy = createIteratorProxy(function () {
 // `Iterator.prototype.map` method
 // https://github.com/tc39/proposal-iterator-helpers
 module.exports = function map(mapper) {
+  anObject(this);
+  aCallable(mapper);
   return new IteratorProxy(getIteratorDirect(this), {
-    mapper: aCallable(mapper)
+    mapper: mapper
   });
 };

packages/core-js/modules/esnext.async-iterator.drop.js

@@ -41,8 +41,10 @@ var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise) {
 // https://github.com/tc39/proposal-async-iterator-helpers
 $({ target: 'AsyncIterator', proto: true, real: true }, {
   drop: function drop(limit) {
+    anObject(this);
+    var remaining = toPositiveInteger(notANaN(+limit));
     return new AsyncIteratorProxy(getIteratorDirect(this), {
-      remaining: toPositiveInteger(notANaN(+limit))
+      remaining: remaining
     });
   }
 });

packages/core-js/modules/esnext.async-iterator.filter.js

@@ -57,8 +57,10 @@ var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise) {
 // https://github.com/tc39/proposal-async-iterator-helpers
 $({ target: 'AsyncIterator', proto: true, real: true }, {
   filter: function filter(predicate) {
+    anObject(this);
+    aCallable(predicate);
     return new AsyncIteratorProxy(getIteratorDirect(this), {
-      predicate: aCallable(predicate)
+      predicate: predicate
     });
   }
 });

packages/core-js/modules/esnext.async-iterator.flat-map.js

@@ -77,8 +77,10 @@ var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise) {
 // https://github.com/tc39/proposal-async-iterator-helpers
 $({ target: 'AsyncIterator', proto: true, real: true }, {
   flatMap: function flatMap(mapper) {
+    anObject(this);
+    aCallable(mapper);
     return new AsyncIteratorProxy(getIteratorDirect(this), {
-      mapper: aCallable(mapper),
+      mapper: mapper,
       inner: null
     });
   }

packages/core-js/modules/esnext.async-iterator.reduce.js

@@ -15,13 +15,14 @@ var $TypeError = TypeError;
 // https://github.com/tc39/proposal-async-iterator-helpers
 $({ target: 'AsyncIterator', proto: true, real: true }, {
   reduce: function reduce(reducer /* , initialValue */) {
+    anObject(this);
+    aCallable(reducer);
     var record = getIteratorDirect(this);
     var iterator = record.iterator;
     var next = record.next;
     var noInitial = arguments.length < 2;
     var accumulator = noInitial ? undefined : arguments[1];
     var counter = 0;
-    aCallable(reducer);
 
     return new Promise(function (resolve, reject) {
       var ifAbruptCloseAsyncIterator = function (error) {

packages/core-js/modules/esnext.async-iterator.take.js

@@ -38,8 +38,10 @@ var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise) {
 // https://github.com/tc39/proposal-async-iterator-helpers
 $({ target: 'AsyncIterator', proto: true, real: true }, {
   take: function take(limit) {
+    anObject(this);
+    var remaining = toPositiveInteger(notANaN(+limit));
     return new AsyncIteratorProxy(getIteratorDirect(this), {
-      remaining: toPositiveInteger(notANaN(+limit))
+      remaining: remaining
     });
   }
 });

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

@@ -26,8 +26,10 @@ var IteratorProxy = createIteratorProxy(function () {
 // https://github.com/tc39/proposal-iterator-helpers
 $({ target: 'Iterator', proto: true, real: true }, {
   drop: function drop(limit) {
+    anObject(this);
+    var remaining = toPositiveInteger(notANaN(+limit));
     return new IteratorProxy(getIteratorDirect(this), {
-      remaining: toPositiveInteger(notANaN(+limit))
+      remaining: remaining
     });
   }
 });

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

@@ -2,15 +2,17 @@
 var $ = require('../internals/export');
 var iterate = require('../internals/iterate');
 var aCallable = require('../internals/a-callable');
+var anObject = require('../internals/an-object');
 var getIteratorDirect = require('../internals/get-iterator-direct');
 
 // `Iterator.prototype.every` method
 // https://github.com/tc39/proposal-iterator-helpers
 $({ target: 'Iterator', proto: true, real: true }, {
   every: function every(predicate) {
+    anObject(this);
+    aCallable(predicate);
     var record = getIteratorDirect(this);
     var counter = 0;
-    aCallable(predicate);
     return !iterate(record, function (value, stop) {
       if (!predicate(value, counter++)) return stop();
     }, { IS_RECORD: true, INTERRUPTED: true }).stopped;

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

@@ -25,8 +25,10 @@ var IteratorProxy = createIteratorProxy(function () {
 // https://github.com/tc39/proposal-iterator-helpers
 $({ target: 'Iterator', proto: true, real: true }, {
   filter: function filter(predicate) {
+    anObject(this);
+    aCallable(predicate);
     return new IteratorProxy(getIteratorDirect(this), {
-      predicate: aCallable(predicate)
+      predicate: predicate
     });
   }
 });

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

@@ -2,15 +2,17 @@
 var $ = require('../internals/export');
 var iterate = require('../internals/iterate');
 var aCallable = require('../internals/a-callable');
+var anObject = require('../internals/an-object');
 var getIteratorDirect = require('../internals/get-iterator-direct');
 
 // `Iterator.prototype.find` method
 // https://github.com/tc39/proposal-iterator-helpers
 $({ target: 'Iterator', proto: true, real: true }, {
   find: function find(predicate) {
+    anObject(this);
+    aCallable(predicate);
     var record = getIteratorDirect(this);
     var counter = 0;
-    aCallable(predicate);
     return iterate(record, function (value, stop) {
       if (predicate(value, counter++)) return stop(value);
     }, { IS_RECORD: true, INTERRUPTED: true }).result;

packages/core-js/modules/esnext.iterator.flat-map.js

@@ -34,8 +34,10 @@ var IteratorProxy = createIteratorProxy(function () {
 // https://github.com/tc39/proposal-iterator-helpers
 $({ target: 'Iterator', proto: true, real: true }, {
   flatMap: function flatMap(mapper) {
+    anObject(this);
+    aCallable(mapper);
     return new IteratorProxy(getIteratorDirect(this), {
-      mapper: aCallable(mapper),
+      mapper: mapper,
       inner: null
     });
   }

packages/core-js/modules/esnext.iterator.for-each.js

@@ -2,15 +2,17 @@
 var $ = require('../internals/export');
 var iterate = require('../internals/iterate');
 var aCallable = require('../internals/a-callable');
+var anObject = require('../internals/an-object');
 var getIteratorDirect = require('../internals/get-iterator-direct');
 
 // `Iterator.prototype.forEach` method
 // https://github.com/tc39/proposal-iterator-helpers
 $({ target: 'Iterator', proto: true, real: true }, {
   forEach: function forEach(fn) {
+    anObject(this);
+    aCallable(fn);
     var record = getIteratorDirect(this);
     var counter = 0;
-    aCallable(fn);
     iterate(record, function (value) {
       fn(value, counter++);
     }, { IS_RECORD: true });

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

@@ -2,6 +2,7 @@
 var $ = require('../internals/export');
 var iterate = require('../internals/iterate');
 var aCallable = require('../internals/a-callable');
+var anObject = require('../internals/an-object');
 var getIteratorDirect = require('../internals/get-iterator-direct');
 
 var $TypeError = TypeError;
@@ -10,8 +11,9 @@ var $TypeError = TypeError;
 // https://github.com/tc39/proposal-iterator-helpers
 $({ target: 'Iterator', proto: true, real: true }, {
   reduce: function reduce(reducer /* , initialValue */) {
-    var record = getIteratorDirect(this);
+    anObject(this);
     aCallable(reducer);
+    var record = getIteratorDirect(this);
     var noInitial = arguments.length < 2;
     var accumulator = noInitial ? undefined : arguments[1];
     var counter = 0;

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

@@ -2,15 +2,17 @@
 var $ = require('../internals/export');
 var iterate = require('../internals/iterate');
 var aCallable = require('../internals/a-callable');
+var anObject = require('../internals/an-object');
 var getIteratorDirect = require('../internals/get-iterator-direct');
 
 // `Iterator.prototype.some` method
 // https://github.com/tc39/proposal-iterator-helpers
 $({ target: 'Iterator', proto: true, real: true }, {
   some: function some(predicate) {
+    anObject(this);
+    aCallable(predicate);
     var record = getIteratorDirect(this);
     var counter = 0;
-    aCallable(predicate);
     return iterate(record, function (value, stop) {
       if (predicate(value, counter++)) return stop();
     }, { IS_RECORD: true, INTERRUPTED: true }).stopped;

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

@@ -23,8 +23,10 @@ var IteratorProxy = createIteratorProxy(function () {
 // https://github.com/tc39/proposal-iterator-helpers
 $({ target: 'Iterator', proto: true, real: true }, {
   take: function take(limit) {
+    anObject(this);
+    var remaining = toPositiveInteger(notANaN(+limit));
     return new IteratorProxy(getIteratorDirect(this), {
-      remaining: toPositiveInteger(notANaN(+limit))
+      remaining: remaining
     });
   }
 });

packages/core-js/modules/esnext.iterator.to-array.js

@@ -1,5 +1,6 @@
 'use strict';
 var $ = require('../internals/export');
+var anObject = require('../internals/an-object');
 var iterate = require('../internals/iterate');
 var getIteratorDirect = require('../internals/get-iterator-direct');
 
@@ -10,7 +11,7 @@ var push = [].push;
 $({ target: 'Iterator', proto: true, real: true }, {
   toArray: function toArray() {
     var result = [];
-    iterate(getIteratorDirect(this), push, { that: result, IS_RECORD: true });
+    iterate(getIteratorDirect(anObject(this)), push, { that: result, IS_RECORD: true });
     return result;
   }
 });

packages/core-js/modules/esnext.iterator.to-async.js

@@ -1,5 +1,6 @@
 'use strict';
 var $ = require('../internals/export');
+var anObject = require('../internals/an-object');
 var AsyncFromSyncIterator = require('../internals/async-from-sync-iterator');
 var WrapAsyncIterator = require('../internals/async-iterator-wrap');
 var getIteratorDirect = require('../internals/get-iterator-direct');
@@ -8,6 +9,6 @@ var getIteratorDirect = require('../internals/get-iterator-direct');
 // https://github.com/tc39/proposal-async-iterator-helpers
 $({ target: 'Iterator', proto: true, real: true }, {
   toAsync: function toAsync() {
-    return new WrapAsyncIterator(getIteratorDirect(new AsyncFromSyncIterator(getIteratorDirect(this))));
+    return new WrapAsyncIterator(getIteratorDirect(new AsyncFromSyncIterator(getIteratorDirect(anObject(this)))));
   }
 });