75 lines
1.8 KiB
TypeScript
75 lines
1.8 KiB
TypeScript
import {describe, expect, it} from 'vitest';
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import {Signal} from '../../src/wrapper.js';
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describe('Computed', () => {
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it('should work', () => {
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const stateSignal = new Signal.State(1);
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const computedSignal = new Signal.Computed(() => {
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const f = stateSignal.get() * 2;
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return f;
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});
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expect(computedSignal.get()).toEqual(2);
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stateSignal.set(5);
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expect(stateSignal.get()).toEqual(5);
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expect(computedSignal.get()).toEqual(10);
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});
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describe('Comparison semantics', () => {
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it('should track Computed by Object.is', () => {
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const state = new Signal.State(1);
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let value = 5;
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let calls = 0;
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const computed = new Signal.Computed(() => (state.get(), value));
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const c2 = new Signal.Computed(() => (calls++, computed.get()));
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expect(calls).toBe(0);
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expect(c2.get()).toBe(5);
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expect(calls).toBe(1);
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state.set(2);
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expect(c2.get()).toBe(5);
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expect(calls).toBe(1);
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value = NaN;
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expect(c2.get()).toBe(5);
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expect(calls).toBe(1);
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state.set(3);
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expect(c2.get()).toBe(NaN);
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expect(calls).toBe(2);
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state.set(4);
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expect(c2.get()).toBe(NaN);
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expect(calls).toBe(2);
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});
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it('applies custom equality in Computed', () => {
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const s = new Signal.State(5);
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let ecalls = 0;
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const c1 = new Signal.Computed(() => (s.get(), 1), {
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equals() {
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ecalls++;
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return false;
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},
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});
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let calls = 0;
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const c2 = new Signal.Computed(() => {
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calls++;
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return c1.get();
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});
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expect(calls).toBe(0);
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expect(ecalls).toBe(0);
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expect(c2.get()).toBe(1);
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expect(ecalls).toBe(0);
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expect(calls).toBe(1);
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s.set(10);
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expect(c2.get()).toBe(1);
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expect(ecalls).toBe(1);
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expect(calls).toBe(2);
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});
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});
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});
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