positional-bind.js

'use strict';

/**
 * Binds function to positioned arguments
 * posargs must be like { 2: one_arg, 100: another_arg, 0: another_arg }
 * @param {Function} fn 
 * @param {Object} posargs 
 */
const positionalBind = (fn, posargs) => (...args) => {
  const indexes = Object.keys(posargs).map(_ => +_).sort();
  const realArgs = [];
  while (indexes.length) {
    realArgs.push(
      indexes[0] === realArgs.length
        ? posargs[indexes.shift()]
        : args.shift());
  }
  return fn(...realArgs, ...args);
};

function fun(a, b, c, d, e) {
  console.log(arguments);
};

const bnd = positionalBind(fun, { 1: 12, 3: 21, 0: 33 });
bnd(44, 55); // [33, 12, 44, 21, 55]

while (indexes.length) {
realArgs.push(
indexes[0] === realArgs.length
? posargs[indexes.shift()]
: args.shift());
}

Without "While() {}"

indexes.concat(args)
    .forEach((value, index) => {
      value = posargs[index];
      realArgs.push(
        !value ? args.shift() : value);
    });