22 lines
488 B
Markdown
22 lines
488 B
Markdown
---
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title: complement
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tags: function,logic,beginner
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firstSeen: 2020-05-13T11:28:33+03:00
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lastUpdated: 2020-09-15T16:28:04+03:00
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---
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Returns a function that is the logical complement of the given function, `fn`.
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- Use the logical not (`!`) operator on the result of calling `fn` with any supplied `args`.
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```js
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const complement = fn => (...args) => !fn(...args);
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```
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```js
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const isEven = num => num % 2 === 0;
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const isOdd = complement(isEven);
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isOdd(2); // false
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isOdd(3); // true
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```
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