2010 12 06 convert to integer

The following will return an Integer with a default of 0 from any String or Number.

    function toInt(number) {
      return number && + number | 0 || 0;
    }
    console.log(toInt("1"));  // 1
    console.log(toInt("1.2"));  // 1
    console.log(toInt("-1.2"));  // -1
    console.log(toInt(1.2));  // 1
    console.log(toInt(0));  // 0
    console.log(toInt("0"));  // 0
    console.log(toInt(Number.NaN));  // 0
    console.log(toInt(1/0));  // 0

Explanation

number && x will return x if number is truthy, and number otherwise.

x || 0 will return x if x is truthy, and 0 otherwise.

+ number will convert number to a Number.

12.34 | 0 will convert 12.34 to the integer 12. It will do it, as all binary operations can only be done on 32 bit integers in JavaScript.

-- @Poetro