How to read an JSON array

Question

How do I read JSON arrays with plain javascript?

Example of the array I need to read:

{
 "GetRouteSummaryForStopResult": {
 "StopNo": "1234",
 "Error": "",
 "StopDescription": "STREET 1 / STREET 2",
 "Routes": {
 "Route": {
 "RouteNo": "1234",
 "RouteHeading": "END_POINT",
 "DirectionID": 1,
 "Direction": "",
 "Trips": {
 "Trip": [
 {
 "Longitude": "-75",
 "Latitude": "45",
 "GPSSpeed": "",
 "TripDestination": "END_POINT",
 "TripStartTime": "10:30",
 "AdjustedScheduleTime": "9",
 "AdjustmentAge": "0.48",
 "LastTripOfSchedule": false,
 "BusType": "NFIN"
 },
 {
 "Longitude": "",
 "Latitude": "",
 "GPSSpeed": "",
 "TripDestination": "END_POINT",
 "TripStartTime": "11:00",
 "AdjustedScheduleTime": "29",
 "AdjustmentAge": "-1",
 "LastTripOfSchedule": false,
 "BusType": ""
 }
 ]
 }
 }
 }
 }
}

I am trying to read Longitude And Latitude To Place in a map.

How would I go about doing this? It is pulled from an external API

I have tried:

function on_page_ld() {
var parse_data = "api.example.com/api_name/?key=abcdefg12345"
var jsonData = JSON.parse();
for (var i = 1; i < jsonData.Routes.Route.RouteNo; i++) {
 var array = jsonData.Routes.Route.RouteNo[i];
 console.log(array);
 }
}

And I get:

VM4059:1 Uncaught SyntaxError: Unexpected token u in JSON at position 0

• Tiklu Ganguly: I see two problems 1) var parse_data = "api.example.com/api_name/?key=abcdefg12345" - you are not downloading this data 2) var jsonData = JSON.parse(); - in your JSON.parse method you need to pass the data that you downloaded in previous line
• Rhett Harrison: stackoverflow.com/questions/46613243/… Checkout this post on SO. Looks like you are passing undefined and that is why it is parsing u at position 0

Answer 1

async function on_page_ld(){
// Fetching data from API
const response = await fetch("api.example.com/api_name/?key=abcdefg12345")
// Parsing JSON
const data = await response.json()
// Your array of latitudes and longitudes
const locations = data.GetRouteSummaryForStopResult.Routes.Route.Trips.Trip
// get all your latitudes and longitudes 
for(i = 0; i < locations.length; i++){
 console.log(i + ") latitude :" + locations[i].latitude);
console.log(i + ") longitude :" + locations[i].longitude);
}
}

• benjm: Thank you! This helped me alot!

Answer 2

You can read the values using a for-in loop

for (i in locations.length) {
 console.log(i + ") latitude :" + locations[i].latitude);
 console.log(i + ") longitude :" + locations[i].longitude);
}