Example 1: merge array in js
//for ES5
var array1 = ["Rahul", "Sachin"];
var array2 = ["Sehwag", "Kohli"];
var output = array1.concat(array2);
console.log(output);
//for ES6, we use spread operators to concat arrays
var array1 = ["Dravid", "Tendulkar"];
var array2 = ["Virendra", "Virat"];
var output = [...array1, ...array2];
console.log(output);
Example 2: js convert array of arrays to array
// Converts array with multiple values into a single array with all items:
var merged = [].concat.apply([], arrays);
Example 3: array flatten
const arr = [1, 2, [3, 4]];
// To flat single level array
arr.flat();
// is equivalent to
arr.reduce((acc, val) => acc.concat(val), []);
// [1, 2, 3, 4]
// or with decomposition syntax
const flattened = arr => [].concat(...arr);
Example 4: concat array javascript
const letters = ['a', 'b', 'c'];
const numbers = [1, 2, 3];
const newArray = letters.concat(numbers);
// newArrat is ['a', 'b', 'c', 1, 2, 3]
Example 5: flatten an array in javascript
// Although this now may be an older version of how to faltten an
// array of arrays. I still want to post it so some may have an understanding
// of how it works
function falltenArray(arr) {
let result = [...arr];
let flattened = false;
let counter = 0;
while (flattened === false){
// checks to see if the element at the counter index is an array
if (Array.isArray(result[counter])){
// unpacks the current array element back into the array
result.splice(counter, 1, ...result[counter]);
// if so the counter should start at the beginning of the array
counter = 0;
} else {
counter += 1;
}
if (counter === result.length){
flattened = true;
}
}
return result;
}
Example 6: js join two arrays
[1,2,3].concat([4,5,6])
// [1,2,3,4,5,6]