| Server IP : 68.65.120.201 / Your IP : 216.73.216.68 Web Server : LiteSpeed System : Linux server179.web-hosting.com 4.18.0-513.18.1.lve.el8.x86_64 #1 SMP Thu Feb 22 12:55:50 UTC 2024 x86_64 User : taxhyuvu ( 2294) PHP Version : 8.1.32 Disable Function : NONE MySQL : OFF | cURL : ON | WGET : ON | Perl : ON | Python : ON | Sudo : OFF | Pkexec : OFF Directory : /home/taxhyuvu/nodevenv/public_html/dp_taxhelplines/10/lib/node_modules/invariant/ |
Upload File : |
# 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)