autobind decorator

A class or method decorator which binds methods to the instance so this is always correct, even when the method is detached.

This is particularly useful for situations like React components, where you often pass methods as event handlers and would otherwise need to .bind(this).

// Before:
<button onClick={ this.handleClick.bind(this) }></button>

// After:
<button onClick={ this.handleClick }></button>

As decorators are a part of future ECMAScript standard they can only be used with transpilers such as Babel.

Note Babel 6 users:

The implementation of the decorator transform is currently on hold as the syntax is not final. If you would like to use this project with Babel 6.0, you may use babel-plugin-transform-decorators-legacy which implement Babel 5 decorator transform for Babel 6.

Installation:

npm install autobind-decorator

Examples:

import autobind from 'autobind-decorator'

class Component {
  constructor(value) {
    this.value = value
  }

  @autobind
  method() {
    return this.value
  }
}

let component = new Component(42)
let method = component.method // .bind(component) isn't needed!
method() // returns 42


// Also usable on the class to bind all methods
@autobind
class Component { }

Alternative

You might want to look at Class instance properties.