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53 lines
892 B
Markdown
53 lines
892 B
Markdown
5 years ago
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# onetime [![Build Status](https://travis-ci.org/sindresorhus/onetime.svg?branch=master)](https://travis-ci.org/sindresorhus/onetime)
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> Only call a function once
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When called multiple times it will return the return value from the first call.
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*Unlike the module [once](https://github.com/isaacs/once), this one isn't naughty extending `Function.prototype`.*
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## Install
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```
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$ npm install --save onetime
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```
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## Usage
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```js
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let i = 0;
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const foo = onetime(() => i++);
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foo(); //=> 0
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foo(); //=> 0
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foo(); //=> 0
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```
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## API
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### onetime(function, [shouldThrow])
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#### function
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Type: `function`
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Function that should only be called once.
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#### shouldThrow
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Type: `boolean`
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Default: `false`
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![](screenshot-shouldthrow.png)
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Set to `true` if you want it to fail with a nice and descriptive error when called more than once.
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## License
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MIT © [Sindre Sorhus](http://sindresorhus.com)
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