Generate a random string
Math.random().toString(36).substr(2);
<span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px">This simply generates a random float, casts it into a String using base 36 and remove the 2 first chars </span>0<span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px"> and </span>.<span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px">.</span>
Clone an array
var newA = myArray.slice(0);
<span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px">This will return a copy of the array, ensuring no other variables point to it.</span>
Remove HTML tags
'<b>A</b>'.replace(/<[^>]+>/gi, '');
<span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px">This is using a simple regular expression to remove any string that looks like </span><xxx><span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px"> where </span>x<span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px"> can be any char, including </span>/<span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px">.</span>
Set a default value
function foo(opts) {
var options = opts || {};
}
<span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px">You will see this in any decent JS code. If </span>opts<span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px"> is defined and not “binarily” </span>false <span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px">it will be assigned to </span>options<span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px">, otherwise it will assign an empty dictionary </span>{}<span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px">.</span>
Reverse a string
var str = "Pouet this string.";
str.split('').reverse().join(''); // "gnirts siht teuoP"
// Keep words order with:
str.split(' ').reverse().join(' '); // "string this Pouet"
<span style="color:rgb(34, 34, 34); font-family:helvetica neue,helvetica,helvetica,arial,sans-serif; font-size:15px">The first example splits on every character, reverses them and puts them back together. The second splits only on words and joins them back separated by a space.</span>