How to get JSON data from JSON file

You can use fetch to get the JSON file.

fetch("../yourFile.JSON").then(res => res.json()).then(data => {
   //do something with your JSON
});

fetch('https://jsonplaceholder.typicode.com/todos/1') .then(res => res.json()).then(json => {
    console.log(json);
});

Newer browsers support the responseType property of the XMLHttpRequest Object and you can set it to 'json' and then get the JSON response with response property of the XMLHttpRequest.

_{Note: responseType='json' is not supported by IE11}

var req = new XMLHttpRequest;
req.responseType = 'json';
req.open('GET', "../yourFile.JSON", true);
req.onload  = function() {
   var json = req.response;
   // do something with your JSON
};
req.send(null);

var req = new XMLHttpRequest;
req.responseType = 'json';
req.open('GET', "https://jsonplaceholder.typicode.com/todos/1", true);
req.onload  = function() {
   var json = req.response;
   console.log(json);
   // do something with your JSON
};
req.send(null);

To support older browsers, you can use XMLHttpRequest and JSON.parse to convert the responseText to JSON.

var req = new XMLHttpRequest;
req.overrideMimeType("application/json");
req.open('GET', "../yourFile.JSON", true);
req.onload  = function() {
   var json = JSON.parse(req.responseText);
   //do something with your JSON
};
req.send(null);

var req = new XMLHttpRequest;
req.overrideMimeType("application/json");
req.open('GET', "https://jsonplaceholder.typicode.com/todos/1", true);
req.onload  = function() {
   var json = JSON.parse(req.responseText);
   console.log(json);
   //do something with your JSON
};
req.send(null);