So, you want to define partials in javascript, eh?

partial.js

// Given a function and a set of arguments, returns a function that, when called, 
// uses the originally given arguments as well as the new arguments. Heavily inspired by
// Clojure: https://clojuredocs.org/clojure.core/partial
// 
// Example:
//    > function logger() { console.log(arguments); }
//    > var prefixedLogger = partial("hi", "there);
//    > prefixedLogger("mom");
//    { '0': 'hi', '1': 'there', '2': 'mom' }
function partial(fn, others) {
  // This is inefficient. See https://github.com/petkaantonov/bluebird/wiki/Optimization-killers#32-leaking-arguments
  var others = Array.prototype.slice.call(arguments, 1); 
  return function() {
    return fn.apply(this, others.concat(Array.prototype.slice.call(arguments))); 
  }
}