Create new array of objects based on two arrays in Javascript

You can combine map with includes:

array1.map(i =>  ({id: i, value: array2.includes(i)}))

Should be simple. Loop through the first array using Array.map & return an object.

const array1 = [20, 2, 35, 86]
const array2 = [8, 86, 15, 23, 35, 44]
const result = array1.map(i => ({ id: i, value: array2.includes(i) }))
console.log(result)

Create a set from the second array:

const a2set = new Set(array2);

then map your first array:

array1.map(v1 => ({id:v1, value: a2set.has(v1)}))

Start a loop against first array and check if that element exists in second array or not.

If element exists push it to array containing objects with flag true or else as false.

const array1 = [20, 2, 35, 86]
const array2 = [8, 86, 15, 23, 35, 44]

var objArray = []
array1.forEach(function(elem){
    objArray.push({
      id : elem,
      value : array2.indexOf(elem) != -1 ? true : false
    });
});

console.log(objArray);

You can use array indexOf to find if the item is inside the second array.

const array1 = [20, 2, 35, 86];
const array2 = [8, 86, 15, 23, 35, 44];

let output = [];
array1.forEach((number) => {
  output.push({
    id: number,
    value: array2.indexOf(number) !== -1
  });
});

console.log(output);

Try a simple for loop:

 
const array1 = [20, 2, 35, 86];
const array2 = [8, 86, 15, 23, 35, 44];
var res = [];
for (var i = 0; i < array1.length; i++) {
  if (array2.includes(array1[i])) {
    res.push({ id: array1[i], value: true });
  } else {
    res.push({ id: array1[i], value: false });
  }
}
console.log(res);

Try the following. If performance is important, or if the arrays might include a large amount of elements, I'd consider using sets for better lookup performance.

const array1 = [20, 2, 35, 86]
const array2 = [8, 86, 15, 23, 35, 44]

const result = array1.map(element => {
    return {
        id: element,
        value: array2.includes(element)
    };
})