Advanced decoder for form-urlencoded data

Usage no npm install needed!

<script type="module">
  import form2json from '';


Build Status

Form2json is a decoder for x-www-form-urlencoded data that supports complex structures. It uses simple dot-notation for nested properties and square brackets to denote arrays.


Here are some examples to illustrate the syntax.

Nested Objects

The following string represents a nested object:

The string will be decoded as:

    planet: {
        name: "Mars",
        diameter: 0.532

There are no restrictions on the nesting-level:


    planet: {
        mars: {
            diameter: 0.532,
            mass: 0.11


Arrays can be encoded using square brackets:


    planets: ["Venus", "Earth", "Mars"]

If the index is omitted, form2json will push the values to the array in order of appearance:


    planets: ["Mars", "Venus", "Earth"]

This feature is really useful, as it allows you to re-order the input fields on the client, without having to update the field names. In order to use this feature with arrays containing nested objects, we have to use a slightly different syntax:


    planets: [
        { name: "Mars", mass: 0.11 },
        { name: "Venus, mass: 0.82 },
        { name: "Earth", mass: 1 }

In fact you may use any non-numerical value as index. All items having the same index will be grouped into one object.