defaults.test.js

import assert from 'assert';
import lodashStable from 'lodash';
import { objectProto } from './utils.js';
import defaults from '../defaults.js';

describe('defaults', function() {
  it('should assign source properties if missing on `object`', function() {
    var actual = defaults({ 'a': 1 }, { 'a': 2, 'b': 2 });
    assert.deepStrictEqual(actual, { 'a': 1, 'b': 2 });
  });

  it('should accept multiple sources', function() {
    var expected = { 'a': 1, 'b': 2, 'c': 3 },
        actual = defaults({ 'a': 1, 'b': 2 }, { 'b': 3 }, { 'c': 3 });

    assert.deepStrictEqual(actual, expected);

    actual = defaults({ 'a': 1, 'b': 2 }, { 'b': 3, 'c': 3 }, { 'c': 2 });
    assert.deepStrictEqual(actual, expected);
  });

  it('should not overwrite `null` values', function() {
    var actual = defaults({ 'a': null }, { 'a': 1 });
    assert.strictEqual(actual.a, null);
  });

  it('should overwrite `undefined` values', function() {
    var actual = defaults({ 'a': undefined }, { 'a': 1 });
    assert.strictEqual(actual.a, 1);
  });

  it('should assign `undefined` values', function() {
    var source = { 'a': undefined, 'b': 1 },
        actual = defaults({}, source);

    assert.deepStrictEqual(actual, { 'a': undefined, 'b': 1 });
  });

  it('should assign properties that shadow those on `Object.prototype`', function() {
    var object = {
      'constructor': objectProto.constructor,
      'hasOwnProperty': objectProto.hasOwnProperty,
      'isPrototypeOf': objectProto.isPrototypeOf,
      'propertyIsEnumerable': objectProto.propertyIsEnumerable,
      'toLocaleString': objectProto.toLocaleString,
      'toString': objectProto.toString,
      'valueOf': objectProto.valueOf
    };

    var source = {
      'constructor': 1,
      'hasOwnProperty': 2,
      'isPrototypeOf': 3,
      'propertyIsEnumerable': 4,
      'toLocaleString': 5,
      'toString': 6,
      'valueOf': 7
    };

    var expected = lodashStable.clone(source);
    assert.deepStrictEqual(defaults({}, source), expected);

    expected = lodashStable.clone(object);
    assert.deepStrictEqual(defaults({}, object, source), expected);
  });
});