es-iterator-helpers
v1.2.0
Published
An ESnext spec-compliant iterator helpers shim/polyfill/replacement that works as far down as ES3.
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es-iterator-helpers
An ESnext spec-compliant sync iterator helpers shim/polyfill/replacement that works as far down as ES3.
This package implements the es-shim API “multi” interface. It works in an ES3-supported environment and complies with the iterator helpers spec and the iterator sequencing spec.
Because the Iterator.prototype
methods depend on a receiver (the this
value), the main export in each subdirectory takes the iterator to operate on as the first argument.
The main export of the package itself is simply an array of the available directory names. It’s sole intended use is for build tooling and testing.
Supported things
Iterator
constructorIterator.prototype
Iterator.concat
Iterator.from
Iterator.prototype.constructor
Iterator.prototype.drop
Iterator.prototype.every
Iterator.prototype.filter
Iterator.prototype.find
Iterator.prototype.flatMap
Iterator.prototype.forEach
Iterator.prototype.map
Iterator.prototype.reduce
Iterator.prototype.some
Iterator.prototype.take
Iterator.prototype.toArray
Environments where this is needed
- node v22, Chrome >= v122: has a bug
- node < v22, Chrome < v122, Safari <= v17.1, Firefox <= v125: not implemented
- all environments lack Iterator.concat
Getting started
npm install --save es-iterator-helpers
Usage/Examples
Using explicit imports:
const map = require('es-iterator-helpers/Iterator.prototype.map');
const toArray = require('es-iterator-helpers/Iterator.prototype.toArray');
const assert = require('assert');
const iterator = [1, 2, 3].values();
const mapped = map(iterator, (x) => x + 10);
assert.deepEqual(
mapped.next(),
{
done: false,
value: 11,
}
);
assert.deepEqual(
toArray(mapped),
[12, 13]
);
Shim using require
:
require('es-iterator-helpers/auto'); // shim all of the methods
require('es-iterator-helpers/Iterator.prototype.map/auto'); // shim the “map” method
Shim using import
syntax:
import 'es-iterator-helpers/auto'; // shim all of the methods
import 'es-iterator-helpers/Iterator.prototype.map/auto'; // shim the “map” method
Tests
Simply clone the repo, npm install
, and run npm test