28 lines
677 B
Markdown
28 lines
677 B
Markdown
|
# warn-once
|
||
|
|
|
||
|
|
Print a warning exactly once during development. Suitable for deprecation warnings, warnings for missing setup etc.
|
||
|
|
|
||
|
|
## Installation
|
||
|
|
|
||
|
|
Open a Terminal in the project root and run:
|
||
|
|
|
||
|
|
```sh
|
||
|
|
npm install warn-once
|
||
|
|
```
|
||
|
|
|
||
|
|
## Usage
|
||
|
|
|
||
|
|
The `warnOnce` function accepts a condition as the first argument. If the condition is `true`, then it'll print a warning:
|
||
|
|
|
||
|
|
```js
|
||
|
|
const warnOnce = require('warn-once');
|
||
|
|
|
||
|
|
// ...
|
||
|
|
|
||
|
|
warnOnce(someCondition, 'This is a warning message');
|
||
|
|
```
|
||
|
|
|
||
|
|
You can call `warnOnce` multiple times, but if the warning was printed already, it'll not be printed again.
|
||
|
|
|
||
|
|
The warning is only shown during development, i.e. if `NODE_ENV` is not set to `'production'`.
|