JSON.stringify doesn't work with normal Javascript array

Question

I must be missing something here, but the following code (Fiddle) returns an empty string:

var test = new Array(); test['a'] = 'test'; test['b'] = 'test b'; var json = JSON.stringify(test); alert(json); 

What is the correct way of JSON'ing this array?

Answer 1

JavaScript arrays are designed to hold data with numeric indexes. You can add named properties to them because an array is a type of object (and this can be useful when you want to store metadata about an array which holds normal, ordered, numerically indexed data), but that isn't what they are designed for.

The JSON array data type cannot have named keys on an array.

When you pass a JavaScript array to JSON.stringify the named properties will be ignored.

If you want named properties, use an Object, not an Array.

const test = {}; // Object  test.a = 'test';  test.b = []; // Array  test.b.push('item');  test.b.push('item2');  test.b.push('item3');  test.b.item4 = "A value"; // Ignored by JSON.stringify  const json = JSON.stringify(test);  console.log(json);