Flatten array

yup just practicing.

JavaScript

function flatten(targetArray, currentArray) {
	if (!currentArray) {
  	currentArray = [];
  }
  for (var i=0; i<targetArray.length; i++) {
  	if (Array.isArray(targetArray[i])) {
    	currentArray.concat(flatten(targetArray[i], currentArray));
    } else {
    	currentArray.push(targetArray[i]);
    }
  }
  return currentArray;
}

console.log(flatten([0, [2, [3, 4]], 3]));