match.js

// $ node --harmony_destructuring match.js -5
'use strict'

let x = Number(process.argv[2])

let { true: a } = {
  [ x > 0 ]: 1,
  [ x < 0 ]: -1,
  [ x === 0 ]: 'wow'
}

console.log(a)

let match = o => {
  let { true: a } = o
  return a
}

let b = match({
  [ x > 0 ]: 1,
  [ x < 0 ]: -1,
  [ x === 0 ]: 'wow'
})

console.log(b)