CODEWITHSUNDEEP
javascriptarraysobject
Mandalina
Mandalina

Reputation: 446

Take array of objects and sort into smaller arrays sorted alphabetically

I am trying to convert an array of objects that looks in this: 

var allApps = [
 {
  title: "amazon",
  summary: "lorem ipsum"
 },
 {
  title: "facebook",
  summary: "lorem ipsum"
 },
 {
  title: "twitter",
  summary: "lorem ipsum"
 },
 {
  title: "flipp",
  summary: "lorem ipsum"
 }
]

Into something that looks like this: 

var titles= {
A: [
    {      
     title: "amazon",
     summary: "lorem ipsum"
    }
],
F: [
     {
      title: "facebook",
      summary: "lorem ipsum"
     },
     {
      title: "flipp",
      summary: "lorem ipsum"
     }
],
T: [
     {
      title: "twitter",
      summary: "lorem ipsum"
     }
   ]
}

So far I have this: 

        var letters = [];
        var titles = [];
        for (var i = 0; i < allApps.length; i++) {
            title = allApps[i].title;
            if (title=="") {
                continue;
            }
            var firstLetter = title.substring(0,1);
            var arrayWithFirstLetter = titles[firstLetter];
            if (arrayWithFirstLetter == null) {
                titles[firstLetter] = [];
                letters.push(firstLetter);
            };
        }

I essentially want to sort the apps based on the title property and push them into the array with the corresponding letter.

Right now my code takes the first letter of each of the titles and creates an array of arrays for each letter

Upvotes: 3

Views: 146

Answers (3)

Barmar
Barmar

Reputation: 782389

You don't need the variable letters. You should be pushing onto titles[firstletter].

And titles should be initialized as an object, not an array.

var allApps = [
 {
  title: "amazon",
  summary: "lorem ipsum"
 },
 {
  title: "facebook",
  summary: "lorem ipsum"
 },
 {
  title: "twitter",
  summary: "lorem ipsum"
 },
 {
  title: "flipp",
  summary: "lorem ipsum"
 }
];

var titles = {};
for (var i = 0; i < allApps.length; i++) {
  title = allApps[i].title;
  if (title == "") {
    continue;
  }
  var firstLetter = title.substring(0, 1).toUpperCase();
  if (!titles[firstLetter]) {
    titles[firstLetter] = [];
  };
  titles[firstLetter].push(allApps[i]);
}

console.log(titles);

Upvotes: 0

duhaime
duhaime

Reputation: 27611

How about:

var allApps = [
 {
  title: "amazon",
  summary: "lorem ipsum"
 },
 {
  title: "facebook",
  summary: "lorem ipsum"
 },
 {
  title: "twitter",
  summary: "lorem ipsum"
 },
 {
  title: "flipp",
  summary: "lorem ipsum"
 }
]

var d = {};
for (var i=0; i<allApps.length; i++) {
  var l = allApps[i].title.substring(0,1);
  // ensure object has key
  if (!d[l]) d[l] = [];
  d[l].push(allApps[i]);
}

console.log(d)

This logs:

{
  a: [
    { title: 'amazon', summary: 'lorem ipsum' }
  ],
  f:[
    { title: 'facebook', summary: 'lorem ipsum' },
    { title: 'flipp', summary: 'lorem ipsum' }
  ],
  t: [
    { title: 'twitter', summary: 'lorem ipsum' }
  ]
}

The idea here is we just loop over allApps, examine the first letter of the title attribute on the current member of that array, then check if that letter is already a key in our new dictionary, d. If not, we add that letter as a key in d. Then we add the current element from allApps to the list of values for that key. That's it!

Upvotes: 1

brk
brk

Reputation: 50346

Use the reduce function and from the current object get the first character. This first character is going to be. If this key exist then update it's value

var allApps = [{
    title: "amazon",
    summary: "lorem ipsum"
  },
  {
    title: "facebook",
    summary: "lorem ipsum"
  },
  {
    title: "twitter",
    summary: "lorem ipsum"
  },
  {
    title: "flipp",
    summary: "lorem ipsum"
  }
]
let k = allApps.reduce(function(acc, curr) {
  let getFirstChar = curr.title.charAt(0).toUpperCase();

  if (acc[getFirstChar] === undefined) {
    acc[getFirstChar] = [];
  }
  acc[getFirstChar].push(curr)
  return acc;



}, {})
console.log(k)

Upvotes: 1

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