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tvardy/curry.js

Last active July 1, 2017 20:10
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  1. tvardy renamed this gist Jul 1, 2017. 1 changed file with 0 additions and 0 deletions.
    0 console output → output
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    File renamed without changes.
  2. tvardy created this gist Jul 1, 2017.
    18 changes: 18 additions & 0 deletions console output
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    2.25
    4
    6
    6.99
    9
    12
    16
    20
    24
    27
    60
    6000
    Hello, world!
    Hello, cousin!
    Hello, babe!
    Good bye, cruel world!
    Very good bye, for ever!!!
    -= END =-
    62 changes: 62 additions & 0 deletions curry.js
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    // the prime hero here
    function curry(func, expectedCount, ...args) {
    function _check(arr) {
    return arr.length >= expectedCount ? _result(arr) : _curry.bind(null, arr)
    }

    function _curry(prev, ...rest) {
    return _check(prev.concat(rest))
    }

    function _result(arr) {
    return func.apply(this, arr)
    }

    return _check(args)
    }

    // 2 simple "workers" to apply currying on
    function multiplyAll(...arr) {
    return arr.reduce((p, c) => p * c, 1)
    }

    function sayTo(type, target, end = '!') {
    return `${type}, ${target}${end}`
    }

    // helper logger
    function log(...args) {
    console.log(args.join('\n'))
    }

    // definitions
    const multiply = curry(multiplyAll, 2) // uses `multiplyAll` worker, expects at least 2 arguments
    const double = multiply(2) // multiples by 2
    const triple = multiply(3) // multiples by 3
    const say = curry(sayTo, 2) // uses `sayTo` worker, expects at least 2 arguments
    const sayHello = say('Hello') // says "Hello, [argument]!"
    const sayHelloBabe = () => sayHello('babe') // says "Hello, babe!"
    const sayGoodBye = say('Good bye') // says "Good bye, [argument]"
    const sayVeryGoodBye = curry(sayTo, 2)('Very good bye') // says "Very good bye, [argument]"

    // running test
    log(
    multiply(1.5)(1.5),
    double(2),
    multiply(2, 3),
    triple(2.33),
    multiply(3)()(3),
    curry(multiplyAll, 3, 2, 3, 2),
    double(2, 4),
    multiply()(4)()(5),
    double(triple(4)),
    triple(3, 3),
    multiply()(3)(4, 5),
    curry(multiplyAll, 3)(10)(20)(30),
    sayHello('world'),
    sayHello()('cousin'),
    sayHelloBabe(),
    sayGoodBye('cruel world'),
    sayVeryGoodBye('for ever', '!!!'),
    '-= END =-'
    )