element-web/test/utils/objects-test.ts

/*
Copyright 2021 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import {
    objectClone,
    objectDiff,
    objectExcluding,
    objectFromEntries,
    objectHasDiff,
    objectKeyChanges,
    objectShallowClone,
    objectWithOnly,
} from "../../src/utils/objects";

describe('objects', () => {
    describe('objectExcluding', () => {
        it('should exclude the given properties', () => {
            const input = { hello: "world", test: true };
            const output = { hello: "world" };
            const props = ["test", "doesnotexist"]; // we also make sure it doesn't explode on missing props
            const result = objectExcluding(input, <any>props); // any is to test the missing prop
            expect(result).toBeDefined();
            expect(result).toMatchObject(output);
        });
    });

    describe('objectWithOnly', () => {
        it('should exclusively use the given properties', () => {
            const input = { hello: "world", test: true };
            const output = { hello: "world" };
            const props = ["hello", "doesnotexist"]; // we also make sure it doesn't explode on missing props
            const result = objectWithOnly(input, <any>props); // any is to test the missing prop
            expect(result).toBeDefined();
            expect(result).toMatchObject(output);
        });
    });

    describe('objectShallowClone', () => {
        it('should create a new object', () => {
            const input = { test: 1 };
            const result = objectShallowClone(input);
            expect(result).toBeDefined();
            expect(result).not.toBe(input);
            expect(result).toMatchObject(input);
        });

        it('should only clone the top level properties', () => {
            const input = { a: 1, b: { c: 2 } };
            const result = objectShallowClone(input);
            expect(result).toBeDefined();
            expect(result).toMatchObject(input);
            expect(result.b).toBe(input.b);
        });

        it('should support custom clone functions', () => {
            const input = { a: 1, b: 2 };
            const output = { a: 4, b: 8 };
            const result = objectShallowClone(input, (k, v) => {
                // XXX: inverted expectation for ease of assertion
                expect(Object.keys(input)).toContain(k);

                return v * 4;
            });
            expect(result).toBeDefined();
            expect(result).toMatchObject(output);
        });
    });

    describe('objectHasDiff', () => {
        it('should return false for the same pointer', () => {
            const a = {};
            const result = objectHasDiff(a, a);
            expect(result).toBe(false);
        });

        it('should return true if keys for A > keys for B', () => {
            const a = { a: 1, b: 2 };
            const b = { a: 1 };
            const result = objectHasDiff(a, b);
            expect(result).toBe(true);
        });

        it('should return true if keys for A < keys for B', () => {
            const a = { a: 1 };
            const b = { a: 1, b: 2 };
            const result = objectHasDiff(a, b);
            expect(result).toBe(true);
        });

        it('should return false if the objects are the same but different pointers', () => {
            const a = { a: 1, b: 2 };
            const b = { a: 1, b: 2 };
            const result = objectHasDiff(a, b);
            expect(result).toBe(false);
        });

        it('should consider pointers when testing values', () => {
            const a = { a: {}, b: 2 }; // `{}` is shorthand for `new Object()`
            const b = { a: {}, b: 2 };
            const result = objectHasDiff(a, b);
            expect(result).toBe(true); // even though the keys are the same, the value pointers vary
        });
    });

    describe('objectDiff', () => {
        it('should return empty sets for the same object', () => {
            const a = { a: 1, b: 2 };
            const b = { a: 1, b: 2 };
            const result = objectDiff(a, b);
            expect(result).toBeDefined();
            expect(result.changed).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toHaveLength(0);
            expect(result.added).toHaveLength(0);
            expect(result.removed).toHaveLength(0);
        });

        it('should return empty sets for the same object pointer', () => {
            const a = { a: 1, b: 2 };
            const result = objectDiff(a, a);
            expect(result).toBeDefined();
            expect(result.changed).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toHaveLength(0);
            expect(result.added).toHaveLength(0);
            expect(result.removed).toHaveLength(0);
        });

        it('should indicate when property changes are made', () => {
            const a = { a: 1, b: 2 };
            const b = { a: 11, b: 2 };
            const result = objectDiff(a, b);
            expect(result.changed).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toHaveLength(1);
            expect(result.added).toHaveLength(0);
            expect(result.removed).toHaveLength(0);
            expect(result.changed).toEqual(['a']);
        });

        it('should indicate when properties are added', () => {
            const a = { a: 1, b: 2 };
            const b = { a: 1, b: 2, c: 3 };
            const result = objectDiff(a, b);
            expect(result.changed).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toHaveLength(0);
            expect(result.added).toHaveLength(1);
            expect(result.removed).toHaveLength(0);
            expect(result.added).toEqual(['c']);
        });

        it('should indicate when properties are removed', () => {
            const a = { a: 1, b: 2 };
            const b = { a: 1 };
            const result = objectDiff(a, b);
            expect(result.changed).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toHaveLength(0);
            expect(result.added).toHaveLength(0);
            expect(result.removed).toHaveLength(1);
            expect(result.removed).toEqual(['b']);
        });

        it('should indicate when multiple aspects change', () => {
            const a = { a: 1, b: 2, c: 3 };
            const b: (typeof a | {d: number}) = { a: 1, b: 22, d: 4 };
            const result = objectDiff(a, b);
            expect(result.changed).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toHaveLength(1);
            expect(result.added).toHaveLength(1);
            expect(result.removed).toHaveLength(1);
            expect(result.changed).toEqual(['b']);
            expect(result.removed).toEqual(['c']);
            expect(result.added).toEqual(['d']);
        });
    });

    describe('objectKeyChanges', () => {
        it('should return an empty set if no properties changed', () => {
            const a = { a: 1, b: 2 };
            const b = { a: 1, b: 2 };
            const result = objectKeyChanges(a, b);
            expect(result).toBeDefined();
            expect(result).toHaveLength(0);
        });

        it('should return an empty set if no properties changed for the same pointer', () => {
            const a = { a: 1, b: 2 };
            const result = objectKeyChanges(a, a);
            expect(result).toBeDefined();
            expect(result).toHaveLength(0);
        });

        it('should return properties which were changed, added, or removed', () => {
            const a = { a: 1, b: 2, c: 3 };
            const b: (typeof a | {d: number}) = { a: 1, b: 22, d: 4 };
            const result = objectKeyChanges(a, b);
            expect(result).toBeDefined();
            expect(result).toHaveLength(3);
            expect(result).toEqual(['c', 'd', 'b']); // order isn't important, but the test cares
        });
    });

    describe('objectClone', () => {
        it('should deep clone an object', () => {
            const a = {
                hello: "world",
                test: {
                    another: "property",
                    test: 42,
                    third: {
                        prop: true,
                    },
                },
            };
            const result = objectClone(a);
            expect(result).toBeDefined();
            expect(result).not.toBe(a);
            expect(result).toMatchObject(a);
            expect(result.test).not.toBe(a.test);
            expect(result.test.third).not.toBe(a.test.third);
        });
    });

    describe('objectFromEntries', () => {
        it('should create an object from an array of entries', () => {
            const output = { a: 1, b: 2, c: 3 };
            const result = objectFromEntries(Object.entries(output));
            expect(result).toBeDefined();
            expect(result).toMatchObject(output);
        });

        it('should maintain pointers in values', () => {
            const output = { a: {}, b: 2, c: 3 };
            const result = objectFromEntries(Object.entries(output));
            expect(result).toBeDefined();
            expect(result).toMatchObject(output);
            expect(result['a']).toBe(output.a);
        });
    });
});