19 lines
450 B
Markdown
19 lines
450 B
Markdown
---
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title: validateNumber
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tags: math,intermediate
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---
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Returns `true` if the given value is a number, `false` otherwise.
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- Use `!isNaN()` in combination with `parseFloat()` to check if the argument is a number.
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- Use `isFinite()` to check if the number is finite.
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- Use `Number()` to check if the coercion holds.
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```js
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const validateNumber = n => !isNaN(parseFloat(n)) && isFinite(n) && Number(n) == n;
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```
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```js
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validateNumber('10'); // true
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```
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