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javascript/snippets/is-number.md

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+---
+title: Value is number
+type: snippet
+tags: [type,math]
+cover: red-petals
+dateModified: 2020-09-15T16:28:04+03:00
+---
+
+Checks if the given argument is a number.
+
+- Use `typeof` to check if a value is classified as a number primitive.
+- To safeguard against `NaN`, check if `val === val` (as `NaN` has a `typeof` equal to `number` and is the only value not equal to itself).
+
+```js
+const isNumber = val => typeof val === 'number' && val === val;
+```
+
+```js
+isNumber(1); // true
+isNumber('1'); // false
+isNumber(NaN); // false
+```