JSON

JSON is a file format for data objects. The objects are structured in attribute–value pairs, where the attribute is a string and the value can be one of the following types:

• Number: 1.14
• String: "foo"
• Boolean: true
• null: null 😄
• Array of other types: ["foo", true, 1.14]
• Object: { "name": "john" }

In JSON documents, whitespace doesn’t matter, and commas go between attribute–value pairs and between items in arrays. Here’s an example, formatted with nice whitespace:

{
  "authors": [
    {
      "name": "john",
      "wearsGlasses": true
    },
    {
      "name": "loren",
      "wearsGlasses": true
    }
  ]
}

It’s also valid JSON to have an array at the top level of the document, e.g.:

[{ "name": "john" }, { "name": "loren" }]

In JavaScript, if we have this document in a string, we can parse it to create a JavaScript object with the same data:

const jsObject = JSON.parse(jsonString)

When working with raw HTTP responses that contain a JSON body, we have to use JSON.parse() to get the data into an object. But we’ll mostly be working with libraries that take care of this step for us.