15 lines
392 B
JavaScript
15 lines
392 B
JavaScript
const expect = require('expect');
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const {once} = require('./_30s.js');
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test('once is a Function', () => {
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expect(once).toBeInstanceOf(Function);
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});
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test('once returns Function', () => {
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expect(typeof once(x => 10)).toBe('function');
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});
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test('once returns the result only once', () => {
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let onced = once(x => x);
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expect(onced(10)).toBe(10);
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expect(onced(10)).toBe(undefined);
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});
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