How to combine first element of one array with first element of second array and second with second and so on

Question

I am having two arrays,

the first array contains:

1, 2, 3, 4, 5

and the second one contains:

100, 200, 300, 400, 500

the result should be:

[ [ '1', '100' ],
  [ '2', '200' ],
  [ '3', '300' ],
  [ '4', '400' ],
  [ '5', '500' ] ]

Answer 1

Simply With forEach method:

const a = [1, 2, 3, 4, 5]
const b = [100, 200, 300, 400, 500]
const c = [];
a.forEach((el, ind) => {
  c.push([el+"", b[ind]+""])
});
console.log(c)

Or with reduce method:

const a = [1, 2, 3, 4, 5]
const b = [100, 200, 300, 400, 500]
const c = a.reduce((acc, curr, ind) => {
  acc.push([curr+"", b[ind]+""]);
  return acc;
}, []);
console.log(c)

Tip: +"" is like doing .toString() will convert number into text

Answer 2

You can loop through the array assuming they are the same size. toString() will give you the strings you want.

const first = [1, 2, 3, 4, 5]
const second = [100, 200, 300, 400, 500]
var result= [];

for(var i=0; i<first.length; i++){
  result.push([first[i].toString(), second[i].toString()]);
}

console.log(result);

If arrays are not the same size and you only want while values exist in both indexes you could check for null or undefined.

const first = [1, 2, 3, 4, 5, 600, 700, 800]
const second = [100, 200, 300, 400, 500, 600, 700]
var result= [];

for(var i=0; i<first.length; i++){
  if(first[i] && second[i]){
    result.push([first[i].toString(), second[i].toString()]);
  }
}

console.log(result);