array.prototype.flatmap (1.3.3)
Published 2026-02-24 13:53:00 +00:00 by atheaadmin
Installation
registry=npm install array.prototype.flatmap@1.3.3"array.prototype.flatmap": "1.3.3"About this package
array.prototype.flatmap 
An ES2019 spec-compliant Array.prototype.flatMap shim/polyfill/replacement that works as far down as ES3.
This package implements the es-shim API interface. It works in an ES3-supported environment and complies with the spec.
Because Array.prototype.flatMap depends on a receiver (the this value), the main export takes the array to operate on as the first argument.
Getting started
npm install --save array.prototype.flatmap
Usage/Examples
var flatMap = require('array.prototype.flatmap');
var assert = require('assert');
var arr = [1, [2], [], 3];
var results = flatMap(arr, function (x, i) {
assert.equal(x, arr[i]);
return x;
});
assert.deepEqual(results, [1, 2, 3]);
var flatMap = require('array.prototype.flatmap');
var assert = require('assert');
/* when Array#flatMap is not present */
delete Array.prototype.flatMap;
var shimmedFlatMap = flatMap.shim();
var mapper = function (x) { return [x, 1]; };
assert.equal(shimmedFlatMap, flatMap.getPolyfill());
assert.deepEqual(arr.flatMap(mapper), flatMap(arr, mapper));
var flatMap = require('array.prototype.flatmap');
var assert = require('assert');
/* when Array#flatMap is present */
var shimmedIncludes = flatMap.shim();
var mapper = function (x) { return [x, 1]; };
assert.equal(shimmedIncludes, Array.prototype.flatMap);
assert.deepEqual(arr.flatMap(mapper), flatMap(arr, mapper));
Tests
Simply clone the repo, npm install, and run npm test
Dependencies
Dependencies
| ID | Version |
|---|---|
| call-bind | ^1.0.8 |
| define-properties | ^1.2.1 |
| es-abstract | ^1.23.5 |
| es-shim-unscopables | ^1.0.2 |
Development Dependencies
| ID | Version |
|---|---|
| @es-shims/api | ^2.5.1 |
| @ljharb/eslint-config | ^21.1.1 |
| auto-changelog | ^2.5.0 |
| encoding | ^0.1.13 |
| eslint | =8.8.0 |
| evalmd | ^0.0.19 |
| for-each | ^0.3.3 |
| has-strict-mode | ^1.0.1 |
| in-publish | ^2.0.1 |
| npmignore | ^0.3.1 |
| nyc | ^10.3.2 |
| object-inspect | ^1.13.3 |
| safe-publish-latest | ^2.0.0 |
| tape | ^5.9.0 |
Keywords
Array.prototype.flatMap
flatMap
array
ESnext
shim
polyfill
flatten
Array.prototype.flatten
es-shim API