Question

This code is to be integrated into an AJAX Chat system to enable a tab auto-completion of user names:

var usernames = new Array();
usernames[0] = "Saladin";
usernames[1] = "Jyllaby";
usernames[2] = "CadaverKindler";
usernames[3] = "qbsuperstar03";

var text = "Text and something else q";

// Start of the script to be imported
var searchTerm = text.slice(text.lastIndexOf(" ") + 1);
var i;
for(i = 0; i < usernames.length && usernames[i].substr(0,searchTerm.length) != searchTerm; i++);
// End of the script to be imported

document.write(usernames[i]);

A couple of notes to be made: The array of usernames and the text variable would both be loaded from the chat itself via AJAX (which, unfortunately, I don’t know), and the final output will be handled by AJAX as well.

Is there a more efficient way to do this?

Also, any tips on how to handle multiple instances of the searchTerm being found?

Answer 1

Micro-optimization: instead of getting the substring and comparing it (creating lots of temporary strings)…

usernames[i].substr(0,searchTerm.length) != searchTerm

…you should use indexOf, which creates no temporary strings…

usernames[i].indexOf(searchTerm) == 0

What do you mean by “multiple instances of the searchTerm being found”? Can you give an example of the problem you’re thinking of?