array-map/test/map.js

`[].map(f)` for older browsers

'use strict';

var map = require('../');
var test = require('tape');

function cripple(xs) {
	xs.map = undefined; // eslint-disable-line no-param-reassign
	return xs;
}

test('numbers -> letters', function (t) {
	t.plan(2);
	var a = map([97, 98, 99], function (c) {
		return String.fromCharCode(c);
	});
	t.equal(a.join(''), 'abc');

	var b = map(cripple([97, 98, 99]), function (c) {
		return String.fromCharCode(c);
	});
	t.equal(b.join(''), 'abc');
});

test('elements and indexes', function (t) {
	t.plan(8);
	var x = { q: 5 };
	var y = 3;
	var z = null;

	t.deepEqual(
		map([x, y, z], function (c, i) { return i; }),
		[ 0, 1, 2 ],
		'index check'
	);
	t.deepEqual(
		map([x, y, z], function (c, i) { return i; }),
		[ 0, 1, 2 ],
		'crippled index check'
	);

	var xs0 = [ x, y, z ];
	map(xs0, function (c, i, xs) {
		t.strictEqual(xs, xs0, 'argument[2]');
	});
	var xs1 = [ x, y, z ];
	map(xs1, function (c, i, xs) {
		t.strictEqual(xs, xs1, 'crippled argument[2]');
	});
});

test('ignore holes', function (t) {
	t.plan(2);
	t.deepEqual(
		map(new Array(5), function (x) { return x; }),
		[]
	);
	t.deepEqual(
		map(cripple(new Array(5)), function (x) { return x; }),
		[]
	);
});

test('sparse map', function (t) {
	t.plan(2);
	var xs = [,, 'a',, 'b']; // eslint-disable-line no-sparse-arrays
	t.equal(
		map(xs, function (x, i) { return x + i; }).join(''),
		'a2b4'
	);

	var ys = [,, 'a',, 'b']; // eslint-disable-line no-sparse-arrays
	t.equal(
		map(cripple(ys), function (x, i) { return x + i; }).join(''),
		'a2b4'
	);
	t.end();
});