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svelte/packages/svelte/tests/signals/test.ts

287 lines
6.9 KiB

import { describe, assert, it } from 'vitest';
import * as $ from '../../src/internal/client/runtime';
import type { ComputationSignal } from '../../src/internal/client/types';
/**
* @param runes runes mode
* @param fn A function that returns a function because we first need to setup all the signals
* and then execute the test in order to simulate a real component
*/
function run_test(runes: boolean, fn: (runes: boolean) => () => void) {
return () => {
// Create a component context to test runes vs legacy mode
$.push({}, runes);
// Create a render context so that effect validations etc don't fail
let execute: any;
const signal = $.render_effect(
() => {
execute = fn(runes);
},
null,
true,
true
);
$.pop();
execute();
$.destroy_signal(signal);
};
}
function test(text: string, fn: (runes: boolean) => any) {
it(`${text} (legacy mode)`, run_test(false, fn));
it(`${text} (runes mode)`, run_test(true, fn));
}
describe('signals', () => {
test('effect with state and derived in it', () => {
const log: string[] = [];
let count = $.source(0);
let double = $.derived(() => $.get(count) * 2);
$.effect(() => {
log.push(`${$.get(count)}:${$.get(double)}`);
});
return () => {
$.flushSync(() => $.set(count, 1));
$.flushSync(() => $.set(count, 2));
assert.deepEqual(log, ['0:0', '1:2', '2:4']);
};
});
test('multiple effects with state and derived in it#1', () => {
const log: string[] = [];
let count = $.source(0);
let double = $.derived(() => $.get(count) * 2);
$.effect(() => {
log.push(`A:${$.get(count)}:${$.get(double)}`);
});
$.effect(() => {
log.push(`B:${$.get(double)}`);
});
return () => {
$.flushSync(() => $.set(count, 1));
$.flushSync(() => $.set(count, 2));
assert.deepEqual(log, ['A:0:0', 'B:0', 'A:1:2', 'B:2', 'A:2:4', 'B:4']);
};
});
test('multiple effects with state and derived in it#2', () => {
const log: string[] = [];
let count = $.source(0);
let double = $.derived(() => $.get(count) * 2);
$.effect(() => {
log.push(`A:${$.get(double)}`);
});
$.effect(() => {
log.push(`B:${$.get(count)}:${$.get(double)}`);
});
return () => {
$.flushSync(() => $.set(count, 1));
$.flushSync(() => $.set(count, 2));
assert.deepEqual(log, ['A:0', 'B:0:0', 'A:2', 'B:1:2', 'A:4', 'B:2:4']);
};
});
test('derived from state', () => {
const log: number[] = [];
let count = $.source(0);
let double = $.derived(() => $.get(count) * 2);
$.effect(() => {
log.push($.get(double));
});
return () => {
$.flushSync(() => $.set(count, 1));
$.flushSync(() => $.set(count, 2));
assert.deepEqual(log, [0, 2, 4]);
};
});
test('derived from derived', () => {
const log: number[] = [];
let count = $.source(0);
let double = $.derived(() => $.get(count) * 2);
let quadruple = $.derived(() => $.get(double) * 2);
$.effect(() => {
log.push($.get(quadruple));
});
return () => {
$.flushSync(() => $.set(count, 1));
$.flushSync(() => $.set(count, 2));
assert.deepEqual(log, [0, 4, 8]);
};
});
test('https://perf.js.hyoo.ru/#!bench=9h2as6_u0mfnn', () => {
let res: number[] = [];
const numbers = Array.from({ length: 2 }, (_, i) => i);
const fib = (n: number): number => (n < 2 ? 1 : fib(n - 1) + fib(n - 2));
const hard = (n: number, l: string) => n + fib(16);
const A = $.source(0);
const B = $.source(0);
const C = $.derived(() => ($.get(A) % 2) + ($.get(B) % 2));
const D = $.derived(() => numbers.map((i) => i + ($.get(A) % 2) - ($.get(B) % 2)));
const E = $.derived(() => hard($.get(C) + $.get(A) + $.get(D)[0]!, 'E'));
const F = $.derived(() => hard($.get(D)[0]! && $.get(B), 'F'));
const G = $.derived(() => $.get(C) + ($.get(C) || $.get(E) % 2) + $.get(D)[0]! + $.get(F));
$.effect(() => {
res.push(hard($.get(G), 'H'));
});
$.effect(() => {
res.push($.get(G));
});
$.effect(() => {
res.push(hard($.get(F), 'J'));
});
return () => {
$.flushSync();
let i = 2;
while (--i) {
res.length = 0;
$.set(B, 1);
$.set(A, 1 + i * 2);
$.flushSync();
$.set(A, 2 + i * 2);
$.set(B, 2);
$.flushSync();
assert.equal(res.length, 4);
assert.deepEqual(res, [3198, 1601, 3195, 1598]);
}
};
});
test('effects correctly handle unowned derived values that do not change', () => {
const log: number[] = [];
let count = $.source(0);
const read = () => {
const x = $.derived(() => ({ count: $.get(count) }));
return $.get(x);
};
const derivedCount = $.derived(() => read().count);
$.user_effect(() => {
log.push($.get(derivedCount));
});
return () => {
$.flushSync(() => $.set(count, 1));
// Ensure we're not leaking consumers
assert.deepEqual(count.c?.length, 1);
$.flushSync(() => $.set(count, 2));
// Ensure we're not leaking consumers
assert.deepEqual(count.c?.length, 1);
$.flushSync(() => $.set(count, 3));
// Ensure we're not leaking consumers
assert.deepEqual(count.c?.length, 1);
assert.deepEqual(log, [0, 1, 2, 3]);
};
});
test('correctly cleanup onowned nested derived values', () => {
return () => {
const nested: ComputationSignal<string>[] = [];
const a = $.source(0);
const b = $.source(0);
const c = $.derived(() => {
const a_2 = $.derived(() => $.get(a) + '!');
const b_2 = $.derived(() => $.get(b) + '?');
nested.push(a_2, b_2);
return { a: $.get(a_2), b: $.get(b_2) };
});
$.get(c);
$.flushSync(() => $.set(a, 1));
$.get(c);
$.flushSync(() => $.set(b, 1));
$.get(c);
// Ensure we're not leaking dependencies
assert.deepEqual(
nested.slice(0, -2).map((s) => s.d),
[null, null, null, null]
);
};
});
// outside of test function so that they are unowned signals
let count = $.source(0);
let calc = $.derived(() => {
if ($.get(count) >= 2) {
return 'limit';
}
return $.get(count) * 2;
});
test('effect with derived using unowned derived every time', () => {
const log: Array<number | string> = [];
const effect = $.user_effect(() => {
log.push($.get(calc));
});
return () => {
$.flushSync(() => $.set(count, 1));
$.flushSync(() => $.set(count, 2));
$.flushSync(() => $.set(count, 3));
$.flushSync(() => $.set(count, 4));
$.flushSync(() => $.set(count, 0));
// Ensure we're not leaking consumers
assert.deepEqual(count.c?.length, 1);
assert.deepEqual(log, [0, 2, 'limit', 0]);
$.destroy_signal(effect);
// Ensure we're not leaking consumers
assert.deepEqual(count.c, null);
};
});
test('schedules rerun when writing to signal before reading it', (runes) => {
if (!runes) return () => {};
const value = $.source({ count: 0 });
$.user_effect(() => {
$.set(value, { count: 0 });
$.get(value);
});
return () => {
let errored = false;
try {
$.flushSync();
} catch (e: any) {
assert.include(e.message, 'ERR_SVELTE_TOO_MANY_UPDATES');
errored = true;
}
assert.equal(errored, true);
};
});
});