element-web/test/utils/maps-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 { EnhancedMap, mapDiff } from "../../src/utils/maps";

describe('maps', () => {
    describe('mapDiff', () => {
        it('should indicate no differences when the pointers are the same', () => {
            const a = new Map([[1, 1], [2, 2], [3, 3]]);
            const result = mapDiff(a, a);
            expect(result).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toBeDefined();
            expect(result.added).toHaveLength(0);
            expect(result.removed).toHaveLength(0);
            expect(result.changed).toHaveLength(0);
        });

        it('should indicate no differences when there are none', () => {
            const a = new Map([[1, 1], [2, 2], [3, 3]]);
            const b = new Map([[1, 1], [2, 2], [3, 3]]);
            const result = mapDiff(a, b);
            expect(result).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toBeDefined();
            expect(result.added).toHaveLength(0);
            expect(result.removed).toHaveLength(0);
            expect(result.changed).toHaveLength(0);
        });

        it('should indicate added properties', () => {
            const a = new Map([[1, 1], [2, 2], [3, 3]]);
            const b = new Map([[1, 1], [2, 2], [3, 3], [4, 4]]);
            const result = mapDiff(a, b);
            expect(result).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toBeDefined();
            expect(result.added).toHaveLength(1);
            expect(result.removed).toHaveLength(0);
            expect(result.changed).toHaveLength(0);
            expect(result.added).toEqual([4]);
        });

        it('should indicate removed properties', () => {
            const a = new Map([[1, 1], [2, 2], [3, 3]]);
            const b = new Map([[1, 1], [2, 2]]);
            const result = mapDiff(a, b);
            expect(result).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toBeDefined();
            expect(result.added).toHaveLength(0);
            expect(result.removed).toHaveLength(1);
            expect(result.changed).toHaveLength(0);
            expect(result.removed).toEqual([3]);
        });

        it('should indicate changed properties', () => {
            const a = new Map([[1, 1], [2, 2], [3, 3]]);
            const b = new Map([[1, 1], [2, 2], [3, 4]]); // note change
            const result = mapDiff(a, b);
            expect(result).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toBeDefined();
            expect(result.added).toHaveLength(0);
            expect(result.removed).toHaveLength(0);
            expect(result.changed).toHaveLength(1);
            expect(result.changed).toEqual([3]);
        });

        it('should indicate changed, added, and removed properties', () => {
            const a = new Map([[1, 1], [2, 2], [3, 3]]);
            const b = new Map([[1, 1], [2, 8], [4, 4]]); // note change
            const result = mapDiff(a, b);
            expect(result).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toBeDefined();
            expect(result.added).toHaveLength(1);
            expect(result.removed).toHaveLength(1);
            expect(result.changed).toHaveLength(1);
            expect(result.added).toEqual([4]);
            expect(result.removed).toEqual([3]);
            expect(result.changed).toEqual([2]);
        });

        it('should indicate changes for difference in pointers', () => {
            const a = new Map([[1, {}]]); // {} always creates a new object
            const b = new Map([[1, {}]]);
            const result = mapDiff(a, b);
            expect(result).toBeDefined();
            expect(result.added).toBeDefined();
            expect(result.removed).toBeDefined();
            expect(result.changed).toBeDefined();
            expect(result.added).toHaveLength(0);
            expect(result.removed).toHaveLength(0);
            expect(result.changed).toHaveLength(1);
            expect(result.changed).toEqual([1]);
        });
    });

    describe('EnhancedMap', () => {
        // Most of these tests will make sure it implements the Map<K, V> class

        it('should be empty by default', () => {
            const result = new EnhancedMap();
            expect(result.size).toBe(0);
        });

        it('should use the provided entries', () => {
            const obj = { a: 1, b: 2 };
            const result = new EnhancedMap(Object.entries(obj));
            expect(result.size).toBe(2);
            expect(result.get('a')).toBe(1);
            expect(result.get('b')).toBe(2);
        });

        it('should create keys if they do not exist', () => {
            const key = 'a';
            const val = {}; // we'll check pointers

            const result = new EnhancedMap<string, any>();
            expect(result.size).toBe(0);

            let get = result.getOrCreate(key, val);
            expect(get).toBeDefined();
            expect(get).toBe(val);
            expect(result.size).toBe(1);

            get = result.getOrCreate(key, 44); // specifically change `val`
            expect(get).toBeDefined();
            expect(get).toBe(val);
            expect(result.size).toBe(1);

            get = result.get(key); // use the base class function
            expect(get).toBeDefined();
            expect(get).toBe(val);
            expect(result.size).toBe(1);
        });

        it('should proxy remove to delete and return it', () => {
            const val = {};
            const result = new EnhancedMap<string, any>();
            result.set('a', val);

            expect(result.size).toBe(1);

            const removed = result.remove('a');
            expect(result.size).toBe(0);
            expect(removed).toBeDefined();
            expect(removed).toBe(val);
        });

        it('should support removing unknown keys', () => {
            const val = {};
            const result = new EnhancedMap<string, any>();
            result.set('a', val);

            expect(result.size).toBe(1);

            const removed = result.remove('not-a');
            expect(result.size).toBe(1);
            expect(removed).not.toBeDefined();
        });
    });
});