Javascript nodejs JSON.parse array

Question

I'm taking a course on udemy and i'm really confused on how notes = JSON.parse(notesString) is an array when it's suppose to be an object (right?) since JSON.parse makes it an object.

var addNote = (title, body) => {
 var notes = []; // Create empty array
 var note = { // Fetch user input
 title,
 body
 };
 try {
 var notesString = fs.readFileSync("notes-data.json"); // Get current notes
 notes = JSON.parse(notesString); // convert current notes into object
 console.log("try:", notes.constructor)
 }catch(e){
 }
 console.log(notes)
 notes.push(note);
 fs.writeFileSync("notes-data.json", JSON.stringify(notes));
};

• zerkms: From this code it looks like it's an array. You commented it's an array yourself: var notes = []; // Create empty array
• zerkms: "since JSON.parse makes it an object" --- it does not. JSON.parse returns the value of the same type it was initially.
• charlietfl: although technically an array is an object in javascript.
• DHARMENDRA SINGH: JSON.parse do just parsing json string into JSON. it can be an array of objects or simple object.

Answer 1

JSON.parse() is required over there because the output of a fs operation is a string which we need to convert into an object in order to access it properly. The data inside it is a JSON Array as a result we are able read it. Add try catch around the JSON.parse because if the data is not of JSON type then it will cause an error.

• simon: This is the proper answer. The key note to remember is that fs operation you're doing returns a //string//, not an object (or array for that matter).
• user6069863: Thank you, it's making sense now.

Answer 2

If JSON in file notes-data.json contains JSON-array, i.e. some content like

[{"one":1}, {"two":2}]

You will get array from JSON.parse method.

Answer 3

If JSON in file notes-data.json contains JSON-array, i.e. some content like

var data = "[{"one":1}, {"two":2}]";
var result = JSON.parse(data);
console.log(result)

• GGO: Please add somes explanations editing your answer, avoid code only answer