biofriction-wp-theme/node_modules/invariant/README.md

38 lines
1.6 KiB
Markdown
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

# invariant
[![Build Status](https://travis-ci.org/zertosh/invariant.svg?branch=master)](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 `proces.env`. See [Server rendering is slower with npm react #812](https://github.com/facebook/react/issues/812)