How to convert two different array values into string in angularJS or javascript

Question

Given these two arrays:

$scope.city= [{id :'NewYork' } , {id : 'Chicago'}];
$scope.color = [{id : 'blue' } , {id : 'Green'}];

I need only the values of both arrays like this:

$scope.string = 'NewYork_Chicago_blue_Green';

Answer 1

Use Array#map to convert each array to an array of strings, then Array#concat them, and Array#join with underscore:

var city = [ {id :'NewYork' } , {id : 'Chicago'}];
var color = [{id : 'blue' } , {id : 'Green'}];

function getId(o) {
  return o.id;
}

var result = city.map(getId).concat(color.map(getId)).join('_');

console.log(result);

Answer 2

You could do that using forEach:

    $scope.constructString = function(arr){
        arr.forEach(function(item){
        if($scope.string && $scope.string.length>0)
            $scope.string += '_';
        $scope.string +=  item.id;
    });

    $scope.constructString($scope.city);
    $scope.constructString($scope.color);

Answer 3

One other way of doing the job could be;

var city = [{id : 'NewYork'}, {id : 'Chicago'}],
   color = [{id : 'blue'}, {id : 'Green'}];
  result = city.concat(color)
               .reduce((p,c,i) => i-1 ? p    + "_" + c.id
                                      : p.id + "_" + c.id);
console.log(result);

Answer 4

Try these steps :

• Array concat() method - used to merge two or more arrays.
• Array join() method - joins all elements of an array into a string.

Working demo :

var city= [ {id :'NewYork' } , {id : 'Chicago'}];

var color = [{id : 'blue' } , {id : 'Green'}];

var cityColor = city.concat(color);

var arr = [];

for (var i in cityColor) {
  arr.push(cityColor[i].id);
}

var str = arr.join('_');

console.log(str);