shift unshift concat push pop splice split in angular6 code example
Example 1: javascript add new array element to start of array
var colors = ["white","blue"];
colors.unshift("red"); //add red to beginning of colors
// colors = ["red","white","blue"]
Example 2: javascript prepend string to array
const names = ["Bob", "Cassandra"]
names.unshift("Alex")
names === ["Alex", "Bob", "Cassandra"]