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33 lines
749 B
Markdown
33 lines
749 B
Markdown
# Check If A Number Is Positive Or Negative
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The
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[`Math`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math)
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module has a handy function for checking if a number is _positive_ or
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_negative_. Or _zero_, for that matter.
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It is
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[`Math.sign`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sign).
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```javascript
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> Math.sign(5)
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1
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> Math.sign(-5)
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-1
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> Math.sign(0)
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0
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```
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Any positive number will result in `1`. Any negative number will result in
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`-1`. If the number happens to be `0`, then `0` will be returned.
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This function goes real well with a switch statement.
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Note also that anything that isn't a number will result in `NaN`.
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```javascript
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> Math.sign("one")
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NaN
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```
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