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author | 2020-11-16 00:10:28 +0100 | |
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committer | 2020-11-16 00:10:28 +0100 | |
commit | e06ec920f7a5d784e674c4c4b4e6d1da3dc7391d (patch) | |
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diff --git a/node_modules/invariant/README.md b/node_modules/invariant/README.md new file mode 100644 index 0000000..4f18354 --- /dev/null +++ b/node_modules/invariant/README.md @@ -0,0 +1,37 @@ +# invariant + +[](https://travis-ci.org/zertosh/invariant) + +A mirror of Facebook's `invariant` (e.g. [React](https://github.com/facebook/react/blob/v0.13.3/src/vendor/core/invariant.js), [flux](https://github.com/facebook/flux/blob/2.0.2/src/invariant.js)). + +A way to provide descriptive errors in development but generic errors in production. + +## Install + +With [npm](http://npmjs.org) do: + +```sh +npm install invariant +``` + +## `invariant(condition, message)` + +```js +var invariant = require('invariant'); + +invariant(someTruthyVal, 'This will not throw'); +// No errors + +invariant(someFalseyVal, 'This will throw an error with this message'); +// Error: Invariant Violation: This will throw an error with this message +``` + +**Note:** When `process.env.NODE_ENV` is not `production`, the message is required. If omitted, `invariant` will throw regardless of the truthiness of the condition. When `process.env.NODE_ENV` is `production`, the message is optional – so they can be minified away. + +### Browser + +When used with [browserify](https://github.com/substack/node-browserify), it'll use `browser.js` (instead of `invariant.js`) and the [envify](https://github.com/hughsk/envify) transform will inline the value of `process.env.NODE_ENV`. + +### Node + +The node version is optimized around the performance implications of accessing `process.env`. The value of `process.env.NODE_ENV` is cached, and repeatedly used instead of reading `process.env`. See [Server rendering is slower with npm react #812](https://github.com/facebook/react/issues/812) |