20 lines
728 B
Markdown
20 lines
728 B
Markdown
### isBrowser
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Determines if the current runtime environment is a browser so that front-end modules can run on the server (Node)
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without throwing errors.
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Use `Array.includes()` on the `typeof` values of both `window` and `document` (globals usually only available in a
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browser environment unless they were explicitly defined), which will return `true` if one of them is `undefined`.
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`typeof` allows globals to be checked for existence without throwing a ReferenceError.
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If both of them are not `undefined`, then the current environment is assumed to be a browser.
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```js
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const isBrowser = () => ![typeof window, typeof document].includes('undefined')
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```
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```js
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isBrowser() // true (browser)
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isBrowser() // false (Node)
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```
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