Javascript toLowerCase（）使用非拉丁字符提供不同的长度

Question

Why JS has problem with capitalized i ( İ ) while javascript is ok with capitalized ş,ö,ç,ğ,ü ( Ş , Ö , Ç , Ğ , Ü ), as stated below? (Problem is not related with the letter position.)

"İş".toLowerCase().length
3
"İŞ".toLowerCase().length
3
"iŞ".toLowerCase().length
2
"iş".toLowerCase().length
2

Moreover

"İ".length
1
"İ".toLowerCase().length
2
"İ".toLocaleLowerCase().length
2

For sceptics, here is screen shot of console where i copied the above codes:

and my charset (which is the first thing I've checked after this problem occurs):

<meta charset="utf-8" />

Thanks in advance.

Answer 1

The issue is the character above capital İ ^← . That is another string value in javascript. You can use .split(); to see the character counts. One more thing to notice it is not just about capital İ but á is also in those list.

You should use String.prototype.toLocaleLowerCase() to locale-specific case mappings.

 console.log("áş".toLocaleLowerCase().split('')); console.log("İş".toLocaleLowerCase().split(''));