Deleting array elements in JavaScript - delete vs splice

Question

What is the difference between using the delete operator on the array element as opposed to using the Array.splice method?

For example:

myArray = [\         


        

Answer 1

The difference can be seen by logging the length of each array after the delete operator and splice() method are applied. For example:

delete operator

var trees = ['redwood', 'bay', 'cedar', 'oak', 'maple'];
delete trees[3];

console.log(trees); // ["redwood", "bay", "cedar", empty, "maple"]
console.log(trees.length); // 5

The delete operator removes the element from the array, but the "placeholder" of the element still exists. oak has been removed but it still takes space in the array. Because of this, the length of the array remains 5.

splice() method

var trees = ['redwood', 'bay', 'cedar', 'oak', 'maple'];
trees.splice(3,1);

console.log(trees); // ["redwood", "bay", "cedar", "maple"]
console.log(trees.length); // 4

The splice() method completely removes the target value and the "placeholder" as well. oak has been removed as well as the space it used to occupy in the array. The length of the array is now 4.