The complete elimination and eradication of JavaScript's this.
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README.md

NO. THIS.

The complete elimination and eradication of JavaScript's this.

nothis demo

If this is so difficult to reason about, why don't we just stop using it? Seriously. Why. don't. we. just. stop. using. it.?

When a function is decorated with the nothis function decorator it will pass this as the first argument. Read more on function decorators here.

Now you can remove all those annoying var self = this lines as they are now completely unnecessary!

Installation

npm install nothis

Functions

  • decorator - @context function decorator for Class functions.
  • nothis - passes this as an argument.
  • fixthis - Prevents the rebinding of this.
  • nothisAll - Prevents the rebinding of this for React.

nothis :: function -> function

Example: Decorator

Basic JavaScript object

import context from 'nothis/contextDecorator'

class Cat {
  sound = 'meow'

  @context
  speak(ctx) {
    return ctx.sound
  }

  @context
  speak2 = ctx => ctx.sound
}

const cat = new Cat()

cat.speak() //=> 'meow'
cat.speak2() //=> 'meow'

Example 1: Basics

Basic JavaScript object

// 😞 GROSS: this
const cat = {
  sound: 'meow',
  speak: function() {
    return this.sound
  }
}

// 🔥 LIT: nothis
import nothis from 'nothis'

const cat = {
  sound: 'meow',
  speak: nothis(function(ctx) {
    return ctx.sound
  })
}

Example 2: Arrow functions

Arrow functions with this won't work. But with nothis you can still access the context.

// 😞 GROSS: this
const cat = {
  sound: 'meow',
  speak: () => this.sound
}
cat.speak()
//=> undefined

// 🔥 LIT: nothis
const cat = {
  sound: 'meow',
  speak: nothis(ctx => ctx.sound)
}
cat.speak()
//=> "meow"

Example 3: Multiple arguments

const cat = {
  sound: 'meow',
  speak: nothis((ctx, end) => ctx.sound + end)
}
cat.speak('!')
// => "meow!"

Example 4: Clarity

Easily know what your context is.

// 😞 GROSS: this
const cat = {
  sound: 'meow',
  speak: function() {
    return this.sound
  },
  crazy: function() {
    setInterval(function() {
      console.log(this.speak())
    }, 1000)
  }
}
cat.speak()
//=> Error: this.speak is not a function

// 🔥 LIT: nothis
const cat = {
  sound: 'meow',
  speak: function() {
    return this.sound
  },
  crazy: nothis(function(ctx) {
    setInterval(function() {
      console.log(ctx.speak())
    }, 1000)
  })
}
cat.crazy()
// => "meow"
// => "meow"
// => "meow"

Example 5: 3rd Party Libraries

3rd party libraries sometimes require you to use this. F that.

// 😞 GROSS: this
$('p').on('click', function() {
  console.log($(this).text())
})

// 🔥 LIT: nothis
$('p').on('click', nothis(ctx => console.log($(ctx).text())))

You can also use parameter destructuring in ES6 arrow functions.

import { EventEmitter2 } from 'eventemitter2'
const events = new EventEmitter2({ wildcard: true })

// 😞 GROSS: this
events.on('button.*', function() {
  console.log('event:', this.event)
})

// 🔥 LIT: nothis + destructuring!
events.on('button.*', nothis(({ event }) => console.log('event', event)))

events.emit('button.click')

fixthis :: object -> object

Sometimes this will get rebound to another context when you least expect it. Consider this example.

// 😞 GROSS: this
const cat = {
  sound: 'meow',
  speak: function() {
    return this.sound
  }
}
const speak = cat.speak

speak()
// => undefined

You can prevent this from happening by using fixthis.

// 🔥 LIT: fixthis
import fixthis from 'nothis/fixthis'

const cat = fixthis({
  sound: 'meow',
  speak: function() {
    return this.sound
  }
})
const speak = cat.speak

speak()
// => "meow"

ES6 Classes

Classes won't save you from the problems of this.

// 😞 GROSS: this
class Cat {
  constructor() {
    this.sound = 'meow'
  }
  speak() {
    return this.sound
  }
}

const cat = new Cat()
const speak = cat.speak
speak()
// => Cannot read property 'sound' of undefined

You still can fixthis it.

// 🔥 LIT: fixthis
class Cat {
  constructor() {
    this.sound = 'meow'
  }
  speak() {
    return this.sound
  }
}

const cat = fixthis(new Cat())
const speak = cat.speak
speak()
//=> "meow"

fixthisReact :: object -> void

Apply fixthisReact to your React component and never have to use this again!

import React from 'react'
import nothisAll from 'nothis/nothisAll'

// 🔥 LIT: no this in sight!
class Counter extends React.Component {
  state = { count: 0 }

  constructor() {
    super()
    nothisAll(this)
  }

  increment({ setState }) {
    setState(({ count }) => ({ count: count + 1 }))
  }

  render({ increment, state }) {
    return (
      <div>
        <button onClick={increment}>{state.count}</button>
      </div>
    )
  }
}

Tombstone - this 1995-2018