unshift
Add an element to the front of an array.
[""].unshift("hello")You might have an array with 3 numbers, like 1, 2, and 3. If you want to add another number to the front, then you unshift it into the array. You do it like this:
let thoseNumbers = [1, 2, 3];
thoseNumbers.unshift(0);Parameters
- item: the element to add to the front of the array.
Example
Make an array that simulates a train. Place the parts of the train in the right order.
let train: string[] = []
let parts = ["flatcar", "boxcar", "tanker", "engine", "flatcar", "caboose", "boxcar"]
while (parts.length > 0) {
let part = parts.shift()
if (parts.length > 1) {
if (part == "engine") {
parts.push(part)
} else if (part == "caboose") {
train.push(part)
} else {
train.unshift(part);
}
} else {
train.unshift(part);
}
}