5 handy Javascript one-liners

one-liners.js

//1. 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 ..

//2. Clone an array:
var newA = myArray.slice(0); 
//This will return a copy of the array, ensuring no other variables point to it.

//3. 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 /.

//4. 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 {}.

//5. Reverse a string:
var str = "Pouet this string."; str.split('').reverse().join(''); // Output: "gnirts siht teuoP"  // Keep words order with: str.split(' ').reverse().join(' '); // Output: "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.