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- 'use strict';
-
- var hasSymbols = require('has-symbols/shams')();
- var forEach = require('for-each');
-
- module.exports = function (assign, t) {
- t.test('error cases', function (st) {
- st['throws'](function () { assign(null); }, TypeError, 'target must be an object');
- st['throws'](function () { assign(undefined); }, TypeError, 'target must be an object');
- st['throws'](function () { assign(null, {}); }, TypeError, 'target must be an object');
- st['throws'](function () { assign(undefined, {}); }, TypeError, 'target must be an object');
- st.end();
- });
-
- t.test('non-object target, no sources', function (st) {
- var bool = assign(true);
- st.equal(typeof bool, 'object', 'bool is object');
- st.equal(Boolean.prototype.valueOf.call(bool), true, 'bool coerces to `true`');
-
- var number = assign(1);
- st.equal(typeof number, 'object', 'number is object');
- st.equal(Number.prototype.valueOf.call(number), 1, 'number coerces to `1`');
-
- var string = assign('1');
- st.equal(typeof string, 'object', 'number is object');
- st.equal(String.prototype.valueOf.call(string), '1', 'number coerces to `"1"`');
-
- st.end();
- });
-
- t.test('non-object target, with sources', function (st) {
- var signal = {};
-
- st.test('boolean', function (st2) {
- var bool = assign(true, { a: signal });
- st2.equal(typeof bool, 'object', 'bool is object');
- st.equal(Boolean.prototype.valueOf.call(bool), true, 'bool coerces to `true`');
- st2.equal(bool.a, signal, 'source properties copied');
- st2.end();
- });
-
- st.test('number', function (st2) {
- var number = assign(1, { a: signal });
- st2.equal(typeof number, 'object', 'number is object');
- st2.equal(Number.prototype.valueOf.call(number), 1, 'number coerces to `1`');
- st2.equal(number.a, signal, 'source properties copied');
- st2.end();
- });
-
- st.test('string', function (st2) {
- var string = assign('1', { a: signal });
- st2.equal(typeof string, 'object', 'number is object');
- st2.equal(String.prototype.valueOf.call(string), '1', 'number coerces to `"1"`');
- st2.equal(string.a, signal, 'source properties copied');
- st2.end();
- });
-
- st.end();
- });
-
- t.test('non-object sources', function (st) {
- st.deepEqual(assign({ a: 1 }, null, { b: 2 }), { a: 1, b: 2 }, 'ignores null source');
- st.deepEqual(assign({ a: 1 }, { b: 2 }, undefined), { a: 1, b: 2 }, 'ignores undefined source');
- st.end();
- });
-
- t.test('returns the modified target object', function (st) {
- var target = {};
- var returned = assign(target, { a: 1 });
- st.equal(returned, target, 'returned object is the same reference as the target object');
- st.end();
- });
-
- t.test('has the right length', function (st) {
- st.equal(assign.length, 2, 'length is 2 => 2 required arguments');
- st.end();
- });
-
- t.test('merge two objects', function (st) {
- var target = { a: 1 };
- var returned = assign(target, { b: 2 });
- st.deepEqual(returned, { a: 1, b: 2 }, 'returned object has properties from both');
- st.end();
- });
-
- t.test('works with functions', function (st) {
- var target = function () {};
- target.a = 1;
- var returned = assign(target, { b: 2 });
- st.equal(target, returned, 'returned object is target');
- st.equal(returned.a, 1);
- st.equal(returned.b, 2);
- st.end();
- });
-
- t.test('works with primitives', function (st) {
- var target = 2;
- var source = { b: 42 };
- var returned = assign(target, source);
- st.equal(Object.prototype.toString.call(returned), '[object Number]', 'returned is object form of number primitive');
- st.equal(Number(returned), target, 'returned and target have same valueOf');
- st.equal(returned.b, source.b);
- st.end();
- });
-
- t.test('merge N objects', function (st) {
- var target = { a: 1 };
- var source1 = { b: 2 };
- var source2 = { c: 3 };
- var returned = assign(target, source1, source2);
- st.deepEqual(returned, { a: 1, b: 2, c: 3 }, 'returned object has properties from all sources');
- st.end();
- });
-
- t.test('only iterates over own keys', function (st) {
- var Foo = function () {};
- Foo.prototype.bar = true;
- var foo = new Foo();
- foo.baz = true;
- var target = { a: 1 };
- var returned = assign(target, foo);
- st.equal(returned, target, 'returned object is the same reference as the target object');
- st.deepEqual(target, { a: 1, baz: true }, 'returned object has only own properties from both');
- st.end();
- });
-
- t.test('includes enumerable symbols, after keys', { skip: !hasSymbols }, function (st) {
- var visited = [];
- var obj = {};
- Object.defineProperty(obj, 'a', { enumerable: true, get: function () { visited.push('a'); return 42; } });
- var symbol = Symbol('enumerable');
- Object.defineProperty(obj, symbol, {
- enumerable: true,
- get: function () { visited.push(symbol); return Infinity; }
- });
- var nonEnumSymbol = Symbol('non-enumerable');
- Object.defineProperty(obj, nonEnumSymbol, {
- enumerable: false,
- get: function () { visited.push(nonEnumSymbol); return -Infinity; }
- });
- var target = assign({}, obj);
- st.deepEqual(visited, ['a', symbol], 'key is visited first, then symbol');
- st.equal(target.a, 42, 'target.a is 42');
- st.equal(target[symbol], Infinity, 'target[symbol] is Infinity');
- st.notEqual(target[nonEnumSymbol], -Infinity, 'target[nonEnumSymbol] is not -Infinity');
- st.end();
- });
-
- t.test('does not fail when symbols are not present', function (st) {
- var getSyms;
- if (hasSymbols) {
- getSyms = Object.getOwnPropertySymbols;
- delete Object.getOwnPropertySymbols;
- }
-
- var visited = [];
- var obj = {};
- Object.defineProperty(obj, 'a', { enumerable: true, get: function () { visited.push('a'); return 42; } });
- var keys = ['a'];
- if (hasSymbols) {
- var symbol = Symbol('sym');
- Object.defineProperty(obj, symbol, {
- enumerable: true,
- get: function () { visited.push(symbol); return Infinity; }
- });
- keys.push(symbol);
- }
- var target = assign({}, obj);
- st.deepEqual(visited, keys, 'assign visits expected keys');
- st.equal(target.a, 42, 'target.a is 42');
-
- if (hasSymbols) {
- st.equal(target[symbol], Infinity);
-
- Object.getOwnPropertySymbols = getSyms;
- }
- st.end();
- });
-
- t.test('preserves correct property enumeration order', function (st) {
- var str = 'abcdefghijklmnopqrst';
- var letters = {};
- forEach(str.split(''), function (letter) {
- letters[letter] = letter;
- });
-
- var n = 5;
- st.comment('run the next test ' + n + ' times');
- var object = assign({}, letters);
- var actual = '';
- for (var k in object) {
- actual += k;
- }
- for (var i = 0; i < n; ++i) {
- st.equal(actual, str, 'property enumeration order should be followed');
- }
- st.end();
- });
-
- t.test('checks enumerability and existence, in case of modification during [[Get]]', { skip: !Object.defineProperty }, function (st) {
- var targetBvalue = {};
- var targetCvalue = {};
- var target = { b: targetBvalue, c: targetCvalue };
- var source = {};
- Object.defineProperty(source, 'a', {
- enumerable: true,
- get: function () {
- delete this.b;
- Object.defineProperty(this, 'c', { enumerable: false });
- return 'a';
- }
- });
- var sourceBvalue = {};
- var sourceCvalue = {};
- source.b = sourceBvalue;
- source.c = sourceCvalue;
- var result = assign(target, source);
- st.equal(result, target, 'sanity check: result is === target');
- st.equal(result.b, targetBvalue, 'target key not overwritten by deleted source key');
- st.equal(result.c, targetCvalue, 'target key not overwritten by non-enumerable source key');
-
- st.end();
- });
- };
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