# deprecation > Log a deprecation message with stack ![build](https://action-badges.now.sh/gr2m/deprecation) ## Usage
Browsers Load `deprecation` directly from [cdn.pika.dev](https://cdn.pika.dev) ```html ```
Node Install with `npm install deprecation` ```js const { Deprecation } = require("deprecation"); // or: import { Deprecation } from "deprecation"; ```
```js function foo() { bar(); } function bar() { baz(); } function baz() { console.warn(new Deprecation("[my-lib] foo() is deprecated, use bar()")); } foo(); // { Deprecation: [my-lib] foo() is deprecated, use bar() // at baz (/path/to/file.js:12:15) // at bar (/path/to/file.js:8:3) // at foo (/path/to/file.js:4:3) ``` To log a deprecation message only once, you can use the [once](https://www.npmjs.com/package/once) module. ```js const Deprecation = require("deprecation"); const once = require("once"); const deprecateFoo = once(console.warn); function foo() { deprecateFoo(new Deprecation("[my-lib] foo() is deprecated, use bar()")); } foo(); foo(); // logs nothing ``` ## License [ISC](LICENSE)