64 lines
1.9 KiB
Markdown
64 lines
1.9 KiB
Markdown
# import-lazy [](https://travis-ci.org/sindresorhus/import-lazy)
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> Import modules lazily
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## Install
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```
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$ npm install --save import-lazy
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```
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## Usage
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```js
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// Pass in `require` or a custom import function
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const importLazy = require('import-lazy')(require);
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const _ = importLazy('lodash');
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// Where you would normally do
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_.isNumber(2);
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// You now instead call it as a function
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_().isNumber(2);
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// It's cached on consecutive calls
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_().isString('unicorn');
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// Extract lazy variations of the props you need
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const members = importLazy('lodash')('isNumber', 'isString');
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// Useful when using destructuring assignment in ES2015
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const {isNumber, isString} = importLazy('lodash')('isNumber', 'isString');
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// Works out of the box for functions and regular properties
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const stuff = importLazy('./math-lib')('sum', 'PHI');
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console.log(stuff.sum(1, 2)); // => 3
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console.log(stuff.PHI); // => 1.618033
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```
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### Proxy support in Node.js 6 or later
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If you use Node.js 6 or later, you can take advantage of ES2015 proxies and don't need to call it as a function.
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```js
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const importLazy = require('import-lazy').proxy(require);
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const _ = importLazy('lodash');
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// No need to call it as a function but still lazily imported
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_.isNumber(2);
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```
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## Related
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- [resolve-from](https://github.com/sindresorhus/resolve-from) - Resolve the path of a module from a given path
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- [import-from](https://github.com/sindresorhus/import-from) - Import a module from a given path
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- [resolve-pkg](https://github.com/sindresorhus/resolve-pkg) - Resolve the path of a package regardless of it having an entry point
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- [lazy-value](https://github.com/sindresorhus/lazy-value) - Create a lazily evaluated value
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- [define-lazy-prop](https://github.com/sindresorhus/define-lazy-prop) - Define a lazily evaluated property on an object
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## License
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MIT © [Sindre Sorhus](https://sindresorhus.com)
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