5 handy JavaScript one-liners

Generate a random string

Math.random().toString(36).substr(2);

This simply generates a random float, casts it into a String using base 36 and remove the 2 first chars 0 and ..

Clone an array

var newA = myArray.slice(0);

This will return a copy of the array, ensuring no other variables point to it.

Remove HTML tags

'<b>A</b>'.replace(/<[^>]+>/gi, '');

This is using a simple regular expression to remove any string that looks like <xxx> where x can be any char, including /.

Set a default value

function foo(opts) { 
   var options = opts || {}; 
}

You will see this in any decent JS code. If opts is defined and not “binarily” false it will be assigned to options, otherwise it will assign an empty dictionary {}.

 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"

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.