Javascript useful methods

javascript_useful_methods.js

// returns a range as a list
function range(start, stop, step) {
  let result = []
  if (step === undefined) {
    step = 1
  }
  if (stop === undefined) {
    stop = start
    start = 0
  }
  if (step > 0) {
    for (let ix = start; ix < stop; ix += step) {
      result.push(ix)
    }
  } else {
    for (let ix = start; ix > stop; ix += step) {
      result.push(ix)
    }
  }
  
  return result
}

let xrange = range

function shuffle(array) {
  var m = array.length, t, i;
  
  // While there remain elements to shuffle…
  while (m) {
    
    // Pick a remaining element…
    i = Math.floor(Math.random() * m--);
    
    // And swap it with the current element.
    t = array[m];
    array[m] = array[i];
    array[i] = t;
  }
  
  return array;
}

// shortcut to sort things
let points = [5,4,2,3,7,1]
points.sort(function(a, b){return b-a});