robonen
96f4cba4a8
- Add array/async/etc. modules and type tests; migrate to eslint flat config and composite tsconfig (vitest typecheck enabled). - Fix PubSub.emit to snapshot listeners before iterating (stable EventEmitter semantics; avoids invoking listeners added during the same emit).
42 lines
1.1 KiB
TypeScript
42 lines
1.1 KiB
TypeScript
import { describe, expect, it } from 'vitest';
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import { compose } from '.';
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describe('compose', () => {
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it('apply functions right-to-left', () => {
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const calc = compose((n: number) => `= ${n}`, (n: number) => n * 2, (n: number) => n + 1);
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expect(calc(3)).toBe('= 8');
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});
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it('pass multiple arguments to the last function', () => {
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const calc = compose((n: number) => n * 10, (a: number, b: number) => a + b);
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expect(calc(2, 3)).toBe(50);
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});
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it('support a single function', () => {
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const inc = compose((n: number) => n + 1);
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expect(inc(1)).toBe(2);
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});
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it('mirror pipe with reversed arguments', () => {
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const f = (n: number) => n + 1;
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const g = (n: number) => n * 2;
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expect(compose(g, f)(3)).toBe(8);
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});
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it('forward this to the right-most function', () => {
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const calc = compose((n: number) => n * 2, function (this: { base: number }, n: number) {
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return this.base + n;
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});
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expect(calc.call({ base: 10 }, 5)).toBe(30);
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});
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it('return the input unchanged with no functions', () => {
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expect((compose as unknown as (...fns: never[]) => (x: number) => number)()(42)).toBe(42);
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});
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});
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