CoffeeScript - The loop variant of while

The loop variant is equivalent to the while loop with true value (while true). The statements in this loop will be executed repeatedly until we exit the loop using the break statement.

Syntax

Given below is the syntax of the loop alternative of the while loop in CoffeeScript.

loop
   statements to be executed repeatedly
   condition to exit the loop

Example

The following example demonstrates the usage of until loop in CoffeeScript. Here we have used the Math function random() to generate random numbers, and if the number generated is 3, we are exiting the loop using break statement. Save this code in a file with name until_loop_example.coffee

loop
   num = Math.random()*8|0
   console.log num
   if num == 5 then break

Open the command prompt and compile the .coffee file as shown below.

c:\> coffee -c loop_example.coffee

On compiling, it gives you the following JavaScript.

// Generated by CoffeeScript 1.10.0
(function() {
  var num;

  while (true) {
    num = Math.random() * 8 | 0;
    console.log(num);
    if (num === 5) {
      break;
    }
  }

}).call(this);

Now, open the command prompt again and run the Coffee Script file as shown below.

c:\> coffee loop_example.coffee

On executing, the CoffeeScript file produces the following output.

2
0
2
3
7
4
6
2
0
1
4
6
5