as-this

Call a javascript function with this referred to the first argument

Primarily a syntactic sugar for CoffeeScript to replace long variable names with '@':

Install

npm install as-this

Usage

• as (self, fn)

  call function, return the self object:

  as = require 'as-this'
  self = {}
  ret = as self, ->
    @msg = 'Hello, World'
  console.log self  # => { msg: 'Hello, World' }
  console.log ret  # => { msg: 'Hello, World' }

• as.call (self, fn)

  get the return value of fn instead of self:

  as = require 'as-this'
  ret = as.call { msg: 'Hello, World' }, ->
    return @msg
  console.log ret  # => 'Hello, World'

• omits self

  parameter self with be assigned to {} if not specified:

  as = require 'as-this'
  ret = as ->
    @msg = 'Hello, World'
  console.log ret  # => { msg: 'Hello, World' }

• defer with promise

  return value with be wrapped as promise if fn returns a promise:

  as = require 'as-this'
  promise = as ->
    new Promise (resolve, reject) =>
      @msg = 'Hello, World'
      resolve()
  promise.then (ret) ->
    console.log ret  # => { msg: 'Hello, World' }

  use co-yield to clean your non-blocking code (not available in browser environment):

  co = require 'co'
  as = require 'as-this'
  co ->
    ret = yield as -> co =>
      @msg = 'Hello, World'
    console.log ret  # => { msg: 'Hello, World' }

• yieldables

  you may use generator function or thunk as fn value, they will be auto wrapped to promise:

  co = require 'co'
  as = require 'as-this'
  co ->
    ret0 = as ->
      @type = 'general'
    ret1 = yield as -> co =>
      @type = 'non-args function returns a promise'
    ret2 = yield as ->
      @type = 'generator function'
      yield []
    ret3 = yield as (cb) ->
      @type = 'thunk'
      cb()
    console.log ret0  # => { type: 'general' }
    console.log ret1  # => { type: 'non-args function returns a promise' }
    console.log ret2  # => { type: 'generator function' }
    console.log ret3  # => { type: 'thunk' }

Scenario

• create object with interdependent properties

  as = require 'as-this'
  urls = as ->
    @base = "http://host:port"
    @main = "#{@base}/main"
    @list = "#{@base}/list"
    @odd = "#{@list}/odd"
    @even = "#{@list}/even"
    ...

  which is functionally equivalent to:

  urls = do ->
    base = "http://host:port"
    list = "#{base}/list"
    return {
      base: base
      main: "#{base}/main"
      list: list
      odd: "#{list}/odd"
      even: "#{list}/even"
    }

• do complex configuration on a specified object

  as = require 'as-this'
  ng = require 'angular'
  
  as (ng.module 'myApp', []), ->
  
    @factory 'myServ', ($http) -> as ->
      @load = (url) ->
        $http.get url
      @update = (url, data) ->
        $http.post url, data
  
    @controller 'myController', ($scope, myServ) -> as $scope, ->
      @doRefresh = ->
        myServ.load 'blahblah.json'
          .then (res) =>
            @data = res
      @doRefresh()