Javascript - Case insensitive Array Search

Question

This code gets rid of all the duplicate variables. Is there a way to make the array search in this function case insensitive?

var x = ["AAA", "aaa", "bbb", "BBB"];

function unique(list) {
  var result = [];
  $.each(list, function(i, e) {
    if ($.inArray(e, result) == -1) result.push(e);
  });
  return result;
}

// Output should be AAA, bbb
console.log(unique(x));

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Associated JSFiddle here

Honestly, the easiest way is to just .toLowerCase() on everything, so that there is a always the same case — Sterling Archer
– Sterling Archer, Commented Mar 19, 2018 at 17:13
Possible duplicate of How do I make Array.indexOf() case insensitive? — ZaidRehman
– ZaidRehman, Commented Dec 17, 2018 at 15:03

Ele · Accepted Answer · 2018-03-19 17:29:19Z

4

You don't need jQuery.
Use the function findIndex and convert to lowerCase every element for each comparison.

var x = ["AAA", "aaa", "bbb", "BBB"];

function unique(list) {
  var result = [];
  list.forEach(function(e) {
    if (result.findIndex(function(r) {
      return r.toLowerCase() === e.toLowerCase();
    }) === -1)
    
    result.push(e);
  });
  
  return result;
}

console.log(unique(x))

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

Using arrow functions:

var x = ["AAA", "aaa", "bbb", "BBB"];

function unique(list) {
  var result = [];
  list.forEach((e) => {
    if (result.findIndex((r) => r.toLowerCase() === e.toLowerCase()) === -1)   
    result.push(e);
  });
  
  return result;
}

console.log(unique(x))

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

edited Mar 19, 2018 at 17:29

answered Mar 19, 2018 at 17:18

Ele

33.8k7 gold badges43 silver badges80 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Anar Sultanov Over a year ago

"A small group of characters, when they are converted to lowercase, cannot make a round trip. To make a round trip means to convert the characters from one locale to another locale that represents character data differently, and then to accurately retrieve the original characters from the converted characters."

Jonas Wilms · Accepted Answer · 2018-03-19 17:16:34Z

0

You could use a lookuptable with only lowercase entries:

function unique(arr){
  const before = new Set, result = [];

  for(const str of arr){
   const lower = str.toLowerCase();
   if(!before.has(lower)){
    before.add(lower);
    result.push(str);
   }
  }
  return result;
}

That in a oneliner:

const unique = arr => (set => arr.filter(el => (lower => !set.has(lower) && set.add(lower))(el.toLowerCase()))(new Set);

answered Mar 19, 2018 at 17:16

Jonas Wilms

139k20 gold badges164 silver badges164 bronze badges

Comments

kishea · Accepted Answer · 2018-03-19 17:40:34Z

-1

just a little tweaking and you will be there

function unique(list) {
    var result = [];
    $.each(list, function(i, e) {
        if($.inArray(e, list)){ result.push(e)};
    });
    return result;
}

that works fine

no need to case change

edited Mar 19, 2018 at 17:40

answered Mar 19, 2018 at 17:33

kishea

6371 gold badge6 silver badges17 bronze badges

Comments

Fraser · Accepted Answer · 2018-03-19 18:11:29Z

-1

Just add .toLowerCase to everything

var x = ["AAA", "aaa", "bbb", "BBB"];

function unique(list) {
  var result = [];
  $.each(list, function(i, e) {
    if ($.inArray(e.toLowerCase(), result) == -1) result.push(e.toLowerCase());
  });
  return result;
}

alert(unique(x));

edited Mar 19, 2018 at 18:11

Fraser

17.2k8 gold badges58 silver badges112 bronze badges

answered Mar 19, 2018 at 17:20

Juan Patrono

1

Collectives™ on Stack Overflow

Javascript - Case insensitive Array Search

4 Answers 4

1 Comment

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

1 Comment

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related