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| 1 | +import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'; |
| 2 | +import { derefWeakRef, makeWeakRef, type MaybeWeakRef } from '../../../src/utils/weakRef'; |
| 3 | + |
| 4 | +describe('Unit | util | weakRef', () => { |
| 5 | + describe('makeWeakRef', () => { |
| 6 | + it('creates a WeakRef when available', () => { |
| 7 | + const obj = { foo: 'bar' }; |
| 8 | + const ref = makeWeakRef(obj); |
| 9 | + |
| 10 | + // Should be a WeakRef, not the direct object |
| 11 | + expect(ref).toBeInstanceOf(WeakRef); |
| 12 | + expect((ref as WeakRef<typeof obj>).deref()).toBe(obj); |
| 13 | + }); |
| 14 | + |
| 15 | + it('returns the object directly when WeakRef is not available', () => { |
| 16 | + const originalWeakRef = globalThis.WeakRef; |
| 17 | + (globalThis as any).WeakRef = undefined; |
| 18 | + |
| 19 | + try { |
| 20 | + const obj = { foo: 'bar' }; |
| 21 | + const ref = makeWeakRef(obj); |
| 22 | + |
| 23 | + // Should be the direct object |
| 24 | + expect(ref).toBe(obj); |
| 25 | + } finally { |
| 26 | + (globalThis as any).WeakRef = originalWeakRef; |
| 27 | + } |
| 28 | + }); |
| 29 | + |
| 30 | + it('returns the object directly when WeakRef constructor throws', () => { |
| 31 | + const originalWeakRef = globalThis.WeakRef; |
| 32 | + (globalThis as any).WeakRef = function () { |
| 33 | + throw new Error('WeakRef not supported'); |
| 34 | + }; |
| 35 | + |
| 36 | + try { |
| 37 | + const obj = { foo: 'bar' }; |
| 38 | + const ref = makeWeakRef(obj); |
| 39 | + |
| 40 | + // Should fall back to the direct object |
| 41 | + expect(ref).toBe(obj); |
| 42 | + } finally { |
| 43 | + (globalThis as any).WeakRef = originalWeakRef; |
| 44 | + } |
| 45 | + }); |
| 46 | + |
| 47 | + it('works with different object types', () => { |
| 48 | + const plainObject = { key: 'value' }; |
| 49 | + const array = [1, 2, 3]; |
| 50 | + const func = () => 'test'; |
| 51 | + const date = new Date(); |
| 52 | + |
| 53 | + expect(derefWeakRef(makeWeakRef(plainObject))).toBe(plainObject); |
| 54 | + expect(derefWeakRef(makeWeakRef(array))).toBe(array); |
| 55 | + expect(derefWeakRef(makeWeakRef(func))).toBe(func); |
| 56 | + expect(derefWeakRef(makeWeakRef(date))).toBe(date); |
| 57 | + }); |
| 58 | + }); |
| 59 | + |
| 60 | + describe('derefWeakRef', () => { |
| 61 | + it('returns undefined for undefined input', () => { |
| 62 | + expect(derefWeakRef(undefined)).toBeUndefined(); |
| 63 | + }); |
| 64 | + |
| 65 | + it('correctly dereferences a WeakRef', () => { |
| 66 | + const obj = { foo: 'bar' }; |
| 67 | + const weakRef = new WeakRef(obj); |
| 68 | + |
| 69 | + expect(derefWeakRef(weakRef)).toBe(obj); |
| 70 | + }); |
| 71 | + |
| 72 | + it('returns the direct object when not a WeakRef', () => { |
| 73 | + const obj = { foo: 'bar' }; |
| 74 | + |
| 75 | + // Passing a direct object (fallback case) |
| 76 | + expect(derefWeakRef(obj as MaybeWeakRef<typeof obj>)).toBe(obj); |
| 77 | + }); |
| 78 | + |
| 79 | + it('returns undefined when WeakRef.deref() returns undefined (simulating GC)', () => { |
| 80 | + const mockWeakRef = { |
| 81 | + deref: vi.fn().mockReturnValue(undefined), |
| 82 | + }; |
| 83 | + |
| 84 | + expect(derefWeakRef(mockWeakRef as MaybeWeakRef<object>)).toBeUndefined(); |
| 85 | + expect(mockWeakRef.deref).toHaveBeenCalled(); |
| 86 | + }); |
| 87 | + |
| 88 | + it('returns undefined when WeakRef.deref() throws an error', () => { |
| 89 | + const mockWeakRef = { |
| 90 | + deref: vi.fn().mockImplementation(() => { |
| 91 | + throw new Error('deref failed'); |
| 92 | + }), |
| 93 | + }; |
| 94 | + |
| 95 | + expect(derefWeakRef(mockWeakRef as MaybeWeakRef<object>)).toBeUndefined(); |
| 96 | + expect(mockWeakRef.deref).toHaveBeenCalled(); |
| 97 | + }); |
| 98 | + |
| 99 | + it('handles objects with a non-function deref property', () => { |
| 100 | + const objWithDerefProperty = { |
| 101 | + deref: 'not a function', |
| 102 | + actualData: 'test', |
| 103 | + }; |
| 104 | + |
| 105 | + // Should treat it as a direct object since deref is not a function |
| 106 | + expect(derefWeakRef(objWithDerefProperty as unknown as MaybeWeakRef<object>)).toBe(objWithDerefProperty); |
| 107 | + }); |
| 108 | + }); |
| 109 | + |
| 110 | + describe('roundtrip (makeWeakRef + derefWeakRef)', () => { |
| 111 | + it('preserves object identity with WeakRef available', () => { |
| 112 | + const obj = { nested: { data: [1, 2, 3] } }; |
| 113 | + const ref = makeWeakRef(obj); |
| 114 | + const retrieved = derefWeakRef(ref); |
| 115 | + |
| 116 | + expect(retrieved).toBe(obj); |
| 117 | + expect(retrieved?.nested.data).toEqual([1, 2, 3]); |
| 118 | + }); |
| 119 | + |
| 120 | + it('preserves object identity with WeakRef unavailable', () => { |
| 121 | + const originalWeakRef = globalThis.WeakRef; |
| 122 | + (globalThis as any).WeakRef = undefined; |
| 123 | + |
| 124 | + try { |
| 125 | + const obj = { nested: { data: [1, 2, 3] } }; |
| 126 | + const ref = makeWeakRef(obj); |
| 127 | + const retrieved = derefWeakRef(ref); |
| 128 | + |
| 129 | + expect(retrieved).toBe(obj); |
| 130 | + expect(retrieved?.nested.data).toEqual([1, 2, 3]); |
| 131 | + } finally { |
| 132 | + (globalThis as any).WeakRef = originalWeakRef; |
| 133 | + } |
| 134 | + }); |
| 135 | + |
| 136 | + it('allows multiple refs to the same object', () => { |
| 137 | + const obj = { id: 'shared' }; |
| 138 | + const ref1 = makeWeakRef(obj); |
| 139 | + const ref2 = makeWeakRef(obj); |
| 140 | + |
| 141 | + expect(derefWeakRef(ref1)).toBe(obj); |
| 142 | + expect(derefWeakRef(ref2)).toBe(obj); |
| 143 | + expect(derefWeakRef(ref1)).toBe(derefWeakRef(ref2)); |
| 144 | + }); |
| 145 | + }); |
| 146 | + |
| 147 | + describe('type safety', () => { |
| 148 | + it('preserves generic type information', () => { |
| 149 | + interface TestInterface { |
| 150 | + id: number; |
| 151 | + name: string; |
| 152 | + } |
| 153 | + |
| 154 | + const obj: TestInterface = { id: 1, name: 'test' }; |
| 155 | + const ref: MaybeWeakRef<TestInterface> = makeWeakRef(obj); |
| 156 | + const retrieved: TestInterface | undefined = derefWeakRef(ref); |
| 157 | + |
| 158 | + expect(retrieved?.id).toBe(1); |
| 159 | + expect(retrieved?.name).toBe('test'); |
| 160 | + }); |
| 161 | + |
| 162 | + it('works with class instances', () => { |
| 163 | + class TestClass { |
| 164 | + constructor(public value: string) {} |
| 165 | + getValue(): string { |
| 166 | + return this.value; |
| 167 | + } |
| 168 | + } |
| 169 | + |
| 170 | + const instance = new TestClass('hello'); |
| 171 | + const ref = makeWeakRef(instance); |
| 172 | + const retrieved = derefWeakRef(ref); |
| 173 | + |
| 174 | + expect(retrieved).toBeInstanceOf(TestClass); |
| 175 | + expect(retrieved?.getValue()).toBe('hello'); |
| 176 | + }); |
| 177 | + }); |
| 178 | +}); |
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