70 lines
2.3 KiB
Markdown
70 lines
2.3 KiB
Markdown
|
# Warning [](https://badge.fury.io/js/warning)
|
||
|
|
|
||
|
|
[](https://greenkeeper.io/)
|
||
|
|
A mirror of Facebook's [Warning](https://github.com/facebook/fbjs/blob/master/packages/fbjs/src/__forks__/warning.js)
|
||
|
|
|
||
|
|
|
||
|
|
## Usage
|
||
|
|
```
|
||
|
|
npm install warning
|
||
|
|
```
|
||
|
|
|
||
|
|
```
|
||
|
|
// some script
|
||
|
|
var warning = require('warning');
|
||
|
|
|
||
|
|
var ShouldBeTrue = false;
|
||
|
|
|
||
|
|
warning(
|
||
|
|
ShouldBeTrue,
|
||
|
|
'This thing should be true but you set to false. No soup for you!'
|
||
|
|
);
|
||
|
|
// 'This thing should be true but you set to false. No soup for you!'
|
||
|
|
```
|
||
|
|
|
||
|
|
Similar to Facebook's (FB) invariant but only logs a warning if the condition is not met.
|
||
|
|
This can be used to log issues in development environments in critical
|
||
|
|
paths. Removing the logging code for production environments will keep the
|
||
|
|
same logic and follow the same code paths.
|
||
|
|
|
||
|
|
## FAQ (READ before opening an issue)
|
||
|
|
|
||
|
|
> Why do you use `console.error` instead of `console.warn` ?
|
||
|
|
|
||
|
|
This is a mirror of Facebook's (FB) [warning](https://github.com/facebook/fbjs/blob/master/packages/fbjs/src/__forks__/warning.js) module used within React's source code (and other FB software).
|
||
|
|
As such this module will mirror their code as much as possible.
|
||
|
|
|
||
|
|
The descision to use `error` over `warn` was made a long time ago by the FB team and isn't going to change anytime soon.
|
||
|
|
|
||
|
|
The source can be found here: https://github.com/facebook/fbjs/blob/master/packages/fbjs/src/__forks__/warning.js
|
||
|
|
The reasoning can be found here and elsewhere: https://github.com/facebook/fbjs/pull/94#issuecomment-168332326
|
||
|
|
|
||
|
|
> Can I add X feature?
|
||
|
|
|
||
|
|
This is a mirror of Facebook's (FB) [warning](https://github.com/facebook/fbjs/blob/master/packages/fbjs/src/__forks__/warning.js) and as such the source and signature will mirror that module.
|
||
|
|
|
||
|
|
If you believe a feature is missing than please open a feature request [there](https://github.com/facebook/fbjs).
|
||
|
|
If it is approved and merged in that this module will be updated to reflect that change, otherwise this module will not change.
|
||
|
|
|
||
|
|
## Use in Production
|
||
|
|
|
||
|
|
It is recommended to add [babel-plugin-dev-expression](https://github.com/4Catalyzer/babel-plugin-dev-expression) with this module to remove warning messages in production.
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
<small>Don't Forget To Be Awesome</small>
|