doing a case insensitive sort in Javascript and getting TypeError: a.toLowerCase is not a function

Question

I have an array (myarray) which contains mixed case values ranging alphabets from a, A , ... z,Z. I am using the following mechanism to sort it irrespective of case that means all capital letters should come first as sorted and then the lowercase ones so that it looks like below after sorting :

Abc, Abd, abs, abp, Back, Bann, bike, ... and so on

I am doing it following way,

var myarray= new Array();
for (i=0; i<select.options.length; i++) {
myarray[i] = new Array();
myarray[i][0] = select.options[i].text;
myarray[i][1] = select.options[i].value;
}           


myarray.sort(function (a, b) {
    return a.toLowerCase().localeCompare(b.toLowerCase());
});

But I am getting the following error :

TypeError: a.toLowerCase is not a function

I am using the most commonly used function but still getting that above error and not finding any solution. Please help me with a better approach or point out what mistake I am making to get that error.

thanks.

toLowerCase is a method of String. Your array probably contains something else. — Álvaro González
– Álvaro González, Commented Nov 30, 2014 at 17:00
Yes , my array does not contain only strings. It is containing some <select> <option> values and text. The full code is posted in my answer, please see below — Abhijit Ghosh
– Abhijit Ghosh, Commented Nov 30, 2014 at 17:13

SkaceKachna · Accepted Answer · 2014-11-30 17:33:17Z

2

You're sorting array that consists of arrays, not strings, so you need to specify what item of array you want to use for sorting.

I don't know if you want to sort array by text or value, but lets assume you want to sort it by option value:

myarray.sort(function (a, b) {
    return a[1].toLowerCase().localeCompare(b[1].toLowerCase());
});

edited Nov 30, 2014 at 17:33

answered Nov 30, 2014 at 17:03

SkaceKachna

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Comments

Grundy · Accepted Answer · 2014-11-30 17:40:56Z

0

So, really you have a nested arrays like

[ ['text1','valie1'],['text2','valie2'],['text2','valie2']]

but when you use your function

myarray.sort(function (a, b) {
    return a.toLowerCase().localeCompare(b.toLowerCase());
});

a and b is array like ['text1','valie1'], not the string

so you need change you sort function like

myarray.sort(function (a, b) {
    var textCompare = a[0].toLowerCase().localeCompare(b[0].toLowerCase());
    var valueCompare =a[1].toLowerCase().localeCompare(b[1].toLowerCase()); 
    return textCompare || valueCompare;
});

also in localeCompare function you can pass locale and options like sensitivity, so you don't need use toLowerCase

edited Nov 30, 2014 at 17:40

answered Nov 30, 2014 at 17:33

Grundy

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