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]; let head = 0; head = 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 count = 0 let part = "" let train: string[] = [] let parts = ["flatcar", "boxcar", "tanker", "engine", "flatcar", "caboose", "boxcar"] while (parts.length > 0) { part = parts.shift() if (parts.length > 1) { if (part == "engine") { parts.push(part) } else if (part == "caboose") { train.push(part) } else { count = train.unshift(part) } } else { count = train.unshift(part) } }