Abstraction.js 2020 Edition (ES6)

abstraction-2020.js

/*
 * Abstraction.js 2020 Edition
 *
 * Copyright (c) 2020 "Cowboy" Ben Alman
 * Licensed under the MIT license.
 * http://benalman.com/about/license/
 */

let $elseif, $else, $if = state => state ? (
  $elseif = () => () => {},
  $else = () => {},
  f => f()
) : (
  $elseif = $if,
  $else = f => f(),
  () => {}
)

usage.js

// Why log now when we can log later?

const abstractify = obj => new Proxy(obj, { get: (o, k) => (...args) => () => o[k](...args) })
const $console = abstractify(console)


// Valid JavaScript

$if (true) (
  $console.log("1")
)
$elseif (true) (
  $console.log("shouldn't log a")
)
$else (
  $console.log("shouldn't log b")
)

$if (false) (
  $console.log("shouldn't log c")
)
$elseif (true) (
  $console.log("2")
)
$elseif (true) (
  $console.log("shouldn't log d")
)
$elseif (false) (
  $console.log("shouldn't log e")
)
$else (
  $console.log("shouldn't log f")
)

$if (false) (
  $console.log("shouldn't log g")
)
$elseif (false) (
  $console.log("shouldn't log h")
)
$else (
  $console.log("3")
)

// Logs:
// 1
// 2
// 3

Prior art:

• Abstraction.js "Lite" (live-coded at BrazilJS 2012)
• Abstraction.js (2012)

Caveat being you can't nest your conditionals.

Caveat being you can't nest your conditionals.

I suppose you could with something like this, but IMO nesting conditionals makes coding too easy

let $elseif, $else, $if = ($ => state => state ? (
  $elseif = () => () => {},
  $else = () => {},
  $
) : (
  $elseif = $if,
  $else = $,
  () => {}
))(($, _ = [$if, $else, $elseif]) => (
  $(), [$if, $else, $elseif] = _
))

$if (true) (()=>{
  $if (false) (
    $console.log("shouldn't log a")
  )
  $elseif (false) (
    $console.log("shouldn't log b")
  )
  $else (
    $console.log("1")
  )
})
$elseif (true) (
  $console.log("shouldn't log c")
)
$else (
  $console.log("shouldn't log d")
)