Use of concat
The concat() method is used to merge two or more arrays. This method does not change the existing array, but returns a new array. If all arguments are omitted, concat returns a shallow copy of the existing array on which this method was called.
<script>
var arr1 = ["k", "a", "i"];
var arr2 = ["m", "o"];
var arr3 = [3, 1, 3];
var result1 = arr1.concat(arr2, arr3);
console.log("result1----->", result1);
var result2 = arr1.concat(arr2, arr3, "hello", 666);
console.log("result2----->", result2);
</script>
Handwritten concat
<script>
Array.prototype.kaimoConcat = function (...args) {
let newArr = [...this];
if (args.length === 0) {
return newArr;
}
args.forEach((el) => {
if (Array.isArray(el)) {
newArr.push(...el);
} else {
newArr.push(el);
}
});
return newArr;
};
var result3 = arr1.kaimoConcat(arr2, arr3);
console.log("result3---kaimoConcat-->", result3);
var result4 = arr1.kaimoConcat(arr2, arr3, "hello", 666);
console.log("result4---kaimoConcat-->", result4);
</script>
