CODEWITHSUNDEEP
javascriptarrayssortingmapping
Hooman Askari
Hooman Askari

Reputation: 1626

Sort a javascript array into nested arrays based on values

I have an array of file names like so:

var filesArray = [
    "120.png",
    "120s.png",
    "120t.jpg",
    "169.png",
    "169r.jpg",
    "169s.jpg",
    "169t.jpg",
    "170.png",
    "170r.jpg",
    "170s.jpg",
    "170t.jpg",
]

Using javascript (es5 or 6 or 7 does not matter since I am using babel) I would like to sort it into a nested array like so:

[
    [
        "120.png",
        "120s.png",
        "120t.jpg"
    ],
    [
        "170.png",
        "170r.jpg",
        "170s.jpg",
        "170t.jpg"
    ]
]

I know that in order to find the same base names I have to run regex and I am already using filesArray[i].slice(0, -4).replace(/[^0-9\.]/g, '') )

What I don't know however is how to run array.sort or array.map to get the final neste array.

By the way, it's long list of file names, and I would prefer the fastest most efficient way to do so without mutating the original array.

Upvotes: 1

Views: 119

Answers (2)

Medet Tleukabiluly
Medet Tleukabiluly

Reputation: 11930

var filesArray = ["120.png", "120s.png", "120t.jpg", "169.png", "169r.jpg", "169s.jpg", "169t.jpg", "170.png", "170r.jpg", "170s.jpg", "170t.jpg"];
var result = [];
var obj = filesArray.reduce(function(prev, curr, index, array) {
  var rawName = curr.match(/[0-9]/g);
  if (rawName.length) {
    var name = rawName.join('');
    if (prev[name]) {
      prev[name].push(curr);
    } else {
      prev[name] = [curr];
    }
  }
  return prev
}, {});

Object.keys(obj).forEach(function(key) {
  result.push(obj[key]);
});
console.log(result);
.as-console-wrapper {
  max-height: 100% !important;
  top: 0;
}
.as-console-row,
.as-console-row-code {
  background-color: #fff!important;
}

Upvotes: 1

Nina Scholz
Nina Scholz

Reputation: 386540

You could use a Map for grouping the items.

var filesArray = ["120.png", "120s.png", "120t.jpg", "169.png", "169r.jpg", "169s.jpg", "169t.jpg", "170.png", "170r.jpg", "170s.jpg", "170t.jpg"],
    grouped = [];

filesArray.forEach(function (a) {
    var key = a.slice(0, -4).replace(/[^0-9\.]/g, ''),
        array = this.get(key);

    if (!array) {
        array = [];
        this.set(key, array);
        grouped.push(array);
    }
    array.push(a);
}, new Map);

console.log(grouped);
.as-console-wrapper { max-height: 100% !important; top: 0; }

Upvotes: 2

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