Javascript interview questions

http://www.quora.com/How-do-you-judge-a-Javascript-programmer-by-only-5-questions

diff between call and apply

call accepts parameters explicitly ... comma seperated
apply accepts array of parameter

call : comma
apply : array

theFunction.apply(param1, ["test1", "test2"]);
theFunction.call(param1, "test1", "test2");


javascript : map and reduce

The reduce() method applies a function against an accumulator and each value of the array (from left-to-right) has to reduce it to a single value.

[0, 1, 2, 3, 4].reduce(function(previousValue, currentValue, index, array) {
  return previousValue + currentValue;
});

The map() method creates a new array with the results of calling a provided function on every element in this array.

var numbers = [1, 4, 9];
var roots = numbers.map(Math.sqrt);
// roots is now [1, 2, 3], numbers is still [1, 4, 9]