JavaScript pre-challenge question

// STEP ONE: You need to take out dashes: make a regex (Regular Expression) with global modifier g to remove dashes from the telephone number string array.

// STEP TWO: Split each one of these telephone numbers to make array with individual digits so its a two dimensional array now (as a result: [ ["1","2","3","4","5"], ["6","7","8","9"],["10","11","12","13"] ] ).

// STEP THREE: Convert all the Strings that you split in each array to Number primitive type so you can add them all up (preferrably using reduction, its perfect for it).

//STEP FOUR: Associate these numbers with their position in the array somehowe (ideally by index, we do have access to indexes through loops and maps); then assign them to point each other altogether in the proper order; using some sort of a data structure for it (object literal for instance, they resemble dictionaries from other languages very well).

// STEP FIVE: Given we have now an Object structure with summed up numbers as KEYS and their VALUES as telephone numbers , they are bound together, and we can find the target via the biggest number key from an Object.

// LAST STEP: Use the biggest number as an accessor for our Object with telephone numbers.

Here's a simple solution (You may, or may not look at it):

var obj = {},
    lastOne,
    dash = new RegExp("-", 'g'),
    myArray = ["720-111-1111","720-999-9999","720-333-3333"];

var n = myArray
.map(function(e) {
  var result = e.replace(dash, "");
  return result;
})
.map(function(e) {
  var number = e.split("")
  number = number.map(function(e) {
    return Number(e);
  });
  var result = number.reduce(function(a,b,i) {
     return a+b  
  });
return result

});

for(var i = 0; i < myArray.length; i++) {
   obj[n[i]] = myArray[i];
}

lastOne = Object.keys(obj)
.map(function(e) {
   return Number(e);
})
.sort(function(a,b) {
  return a > b;
});

lastOne = obj[lastOne[lastOne.length-1]];
alert(lastOne);

Maciej Sitko I like your answer but that is a lot for someone that is just getting into programming to comprehend. Another thing to consider is that the interviewer is looking to see how the interviewee problem solved and how they learn.

Ryan it sounds like you are going down the right path, turning it into smaller steps. I would worry less about the big solution and focus on getting the little things working. This might not be the answer you are looking for but it is better to have an incomplete solution that you can understand than a solution that works and you dont know what is going on.

I had to answer the same question about a year ago and had no idea what I was doing. I submitted an awful function but I could explain what I had learned and I got into the full stack program I am in now.

some resources : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide, http://eloquentjavascript.net/, treehouse, google everything!