19 lines
349 B
Markdown
19 lines
349 B
Markdown
---
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title: isUndefined
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tags: type,beginner
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firstSeen: 2018-01-16T16:50:21+02:00
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lastUpdated: 2020-10-20T23:02:01+03:00
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---
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Checks if the specified value is `undefined`.
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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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