13 lines
397 B
JavaScript
13 lines
397 B
JavaScript
const expect = require('expect');
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const countBy = require('./countBy.js');
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test('countBy is a Function', () => {
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expect(countBy).toBeInstanceOf(Function);
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});
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test('Works for functions', () => {
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expect(countBy([6.1, 4.2, 6.3], Math.floor)).toEqual({ 4: 1, 6: 2 });
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});
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test('Works for property names', () => {
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expect(countBy(['one', 'two', 'three'], 'length')).toEqual({ 3: 2, 5: 1 });
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});
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