JSON Parse

JSON Parse

JSON.parse() converts a JSON string into a JavaScript object.

The problem

When a server sends data, it arrives as text. To use it in your code, you must parse it.

const jsonText = '{"name": "Ada", "age": 36}';
const obj = JSON.parse(jsonText);
obj.name; // "Ada"
obj.age;  // 36

Why parse?

Before parsing, the data is just a string. After parsing, it becomes a real object you can read and modify.

Parsing arrays

const jsonArray = '[1, 2, 3]';
const arr = JSON.parse(jsonArray);
arr[0]; // 1

Handling errors

If the text is not valid JSON, parse throws an error. Wrap it in try/catch:

try {
  JSON.parse("not json");
} catch (err) {
  console.log("Bad JSON");
}

TL;DR

• JSON.parse turns JSON text into an object.
• Data from servers is text, so parse it first.
• Invalid JSON throws an error.
• Use try/catch to handle bad input.