Merge Arrays in one with ES6 Array spread

gistfile1.txt

const arr1 = [1,2,3]
const arr2 = [4,5,6]
const arr3 = [...arr1, ...arr2] //arr3 ==> [1,2,3,4,5,6]

@eveevans exactly, that's one of the best parts from this feature, it also allows you to make array clones.

const arr1 = [1, 2, 3]; // [1, 2, 3]
const arr2 = [...arr1]; //  [1, 2, 3]
arr2[1] = 5; //                 [1, 5, 3]
console.log(arr1); //       [1, 2, 3]

const arr1 = [1, 2, 3]; // [1, 2, 3]
const arr2 = [3, 4, 5]; // [3, 4, 5]

const concatArr = [...arr1, ...arr2]; // [1, 2, 3, 3, 4, 5]
const mergedArr = Array.from(new Set([...concatArr])); // [1, 2, 3, 4, 5]

refer
https://www.interfacecreator.com/2018/09/typescript-array-type-script-type-test.html

const arrayOne = [{ a: "a" }, { b: "b" }, { c: "c" }];
const arrayTwo = [{ d: "d" }, { e: "e" }, { f: "f" }];
const arrayMerge = { ...arrayOne, ...arrayTwo };
console.log(arrayMerge);

this will result { '0': { d: 'd' }, '1': { e: 'e' }, '2': { f: 'f' } }

How can i remove the indices and merge the array because as you see the result is only arrayTwo

@basilbattikhi First of all if you are trying to merge two arrays, the result will be an array(obvious).
Try this,

const arrayOne = [{ a: "a" }, { b: "b" }, { c: "c" }];
const arrayTwo = [{ d: "d" }, { e: "e" }, { f: "f" }];
const arrayMerge = [ ...arrayOne, ...arrayTwo ];
console.log(arrayMerge);

I've noticed a quirk behavior with spread for flattening an array of arrays.
With concat it goes one level deeper //res = [1,2,9,3,4,5,6]

let arrays = [ [1, [2, 9,], 3], [4, [5], [6]] ];

const res = arrays.reduce((acc, curr) => {
   return acc.concat(...curr);
}, []);

This only goes one level of nesting //res = [1, [2,9], 3, 4, [5], [6]]

let arrays = [ [1, [2, 9,], 3], [4, [5], [6]] ];
const res = arrays.reduce((acc, curr) => {
    return [...acc, ...curr];
}, []);

When you want to merge Objects in Array, then

[{a: 1, b: 2}, {a: 3, b: 4}, {a: 5, b: 6, c: 7}].reduce((acc, curr) => ({...acc, ...curr}), {});

will result

{a: 5, b: 6, c: 7}

ddoooppppeeeeee....easiest answer ive ever googled

This is so strange.. I rather use arr3= arr1.concat(arr2)

This way has a lot of performance issues

_travelDevs

Thanks.. Its working. You make my day

I'm getting an error jQuery is not defined?

this es6 solution is also pretty cool
const concat = (...args) => args.flat();
concat([1, 2, 3], [4, 5], [6, 7]); //➞ [1, 2, 3, 4, 5, 6, 7]

I'm getting an error jQuery is not defined?

You need to add jQuery external link in script tag

arr3 = [...arr1, ...arr2]; will fail if any of them are null.

const arr = [[1,2,3], [4,5,6]]
const merged = arr.reduce((a, b) => { a.splice(0, 0, b); return a; }, [])