Package Exports

array.prototype.flatmap
array.prototype.flatmap/auto
array.prototype.flatmap/auto.js
array.prototype.flatmap/index.js
array.prototype.flatmap/shim
array.prototype.flatmap/shim.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (array.prototype.flatmap) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

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