How to print two array lists in an object in JavaScript

You can do it with the help of Array.prototype.reduce:

const myArr = [0,-1,2,-3,4,-5,6];

const result = myArr.reduce((all, item) => {

    const key = item >= 0 ? 'Positive' : 'Negative';

    all[key].push(item);

    return all;

}, {Positive: [], Negative: []});

console.log(result);

As far as I see your array definition, you are using JavaScript - don't forget to add the tag javascript.

You need the following output:

var obj = {positive: new Array(), negative: new Array()};

Iterate once through all the elements and add them to the correct array:

var myArr = [0,-1,2,-3,4,-5,6];
var obj = {positive: new Array(), negative: new Array()};
myArr.forEach(i => { 
    if (i>=0) { obj.positive.push(i) } else { obj.negative.push(i); }
});
console.log(JSON.stringify(obj));

The result obj will have the following arrays:

negative : (3) [-1, -3, -5]
positive : (4) [0, 2, 4, 6]

Printed out with JSON.stringify(obj) will result in:

{"positive":[0,2,4,6],"negative":[-1,-3,-5]}

If you need to do it in JavaScript, you can do so

let myArr = [0,-1,2,-3,4,-5,6];
let obj = {Positive: myArr.filter(e => e < 0), Negative: myArr.filter(e => e >= 0)};
console.log(obj);

You can be explicit, and is totally find

const numbers = [0, -1, 2, -3, 4, -5, 6];
const positives = numbers.filter(number => number >= 0);
const negatives = numbers.filter(number => number < 0)
const results = {positives: positives, negatives: negatives}

console.log(results); // {positives: [0, 2, 4 ,6], negatives: [-1, -3, -5]}

I attached an executable example

const numbers = [0, -1 , 2, -3, 4, -5, 6];
const positives = numbers.filter(number => number >= 0);
const negatives = numbers.filter(number => number < 0);
const results = {positives: positives, negatives: negatives};

console.log(results);