class-bind

class-bind is a utility to make certain methods of a class be bound on access.

It's careful to preserve things like C.prototype.foo giving the original function and the enumerable/writable/configurable flags.

Why?

The main motivation was meta-programming in development. If a method on the prototype is assigned to, it will also be autobound and instances will receive it on the next access. This is disabled in production for performance reasons.

Also I couldn't find anything that let me use decorators to say what should be bound.

Example

import {bound, bind, bindAll} from 'class-bind';
 
class A {
    // bound with a decorator
    @bound
    foo(){ return this.x; }
 
    bar(){ return this.y; }
}
 
 
// bind a single method
bind(A.prototype, 'bar');
 
// or bind every method
bindAll(A.prototype);

Install

npm install --save class-bind

Docs

bound

bound is intended to be used as a decorator. Look at the [src/bind.js][src/bind.js] for an example of how it'd work without a decorator.

bind

Takes a protoype and a key, and replaces it with a modified descriptor. It's just bound + Object.defineProperty.

bindAll

Takes a prototype, binds all own property methods. It's just Object.getOwnPropertyNames + bind.

Usage

process.env.NODE_ENV

If this is running in node or browserify: cool. If it's webpack, you need to use DefinePlugin to provide it.

If you don't do this correctly you'll get an error, e.g. in v8:

ReferenceError: process is not defined
TypeError: Cannot read property 'NODE_ENV' of undefined

Paths

require('class-bind') would give you an object with the three functions above. It resolves to class-bind/lib/index.js', which is es5.

Alternatively, you can e.g. require('class-bind/lib/bound') to just get a single function.

The source is es6 and can be found in class-bind/src.

Development

The ususal npm stuff:

# prepare environment
npm install

# run tests
npm test

# es6 in src -> es5 in lib
npm run prepublish