How to make an array from JSON?

Question

Couldn't think of better title. Important to note: I'm new to js and I guess its the reason I can't figure it out by myself.

I have a JSON array returned from a database, the JSON array represent a set of points. Example of the JSON array:

var JSON_array = [{lat:1,lng:2}, {lat:1,lng:3},{lat:2,lng:3}...]

I want to make a different array whose elements will be a function and the variables of the function will be the elements from the JSON array, like so:

var coordinates = [
new google.maps.LatLng(1, 2),
new google.maps.LatLng(1, 3),
new google.maps.LatLng(2, 3),
....
];

I made a function using forEach that counts the elements of the JSON array (for learning and trying to find a way to what I want) but I cant think of a way make the array mentioned above.

Answer 1

You could use Array map method:

var coordinates = JSON_array.map(function(coordinate) {
    return new google.maps.LatLng(coordinate.lat, coordinate.lng);
})

This method gives you an new array based on (1) the original array and (2) how you deal with each element. Here's more detailed doc for the method.

Answer 2

you can also use regular for loop

coordinates = [];
for(var i=0;i<JSON_array.length;i++){
    coordinates.push(new google.maps.LatLng(JSON_array[i].lat,JSON_array[i].lng));
}

Answer 3

For mapping element from one array to another you can use Array.prototype.map function like

var JSON_array = [{lat:1,lng:2}, {lat:1,lng:3},{lat:2,lng:3}...];
var coordinates = JSON_array.map(function(el){ return new google.maps.LatLng(el.lat, el.lng)});

Answer 4

As Grundy commented you can just do:

coordinates = JSON_array.map(function(x) {
                                 return new google.maps.LatLng(x.lat, x.lng);
                             });

You might want to get your nomenclature straight though, this has nothing to do with JSON.