17 lines
298 B
Markdown
17 lines
298 B
Markdown
---
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title: isUndefined
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tags: type,beginner
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---
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Returns `true` if the specified value is `undefined`, `false` otherwise.
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Use the strict equality operator to check if `val` is equal to `undefined`.
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```js
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const isUndefined = val => val === undefined;
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```
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```js
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isUndefined(undefined); // true
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```
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