Adds one or more elements to the beginning of an array and returns the new length of the array.
|ECMAScript Edition||ECMAScript 3rd Edition|
arrayName.unshift(element1, ..., elementN)
element1, ..., elementN
- The elements to add to the front of the array.
length property of the object upon which the method was called.
unshift method inserts the given values to the beginning of an array-like object.
unshift is intentionally generic; this method can be called or applied to objects resembling arrays. Objects which do not contain a
length property reflecting the last in a series of consecutive, zero-based numerical properties may not behave in any meaningful manner.
var arr = [1, 2]; arr.unshift(0); //result of call is 3, the new array length //arr is [0, 1, 2] arr.unshift(-2, -1); // = 5 //arr is [-2, -1, 0, 1, 2] arr.unshift( [-3] ); //arr is [[-3], -2, -1, 0, 1, 2]