Nicely Presented Misnomer

    TypeScript icon, indicating that this package has built-in type declarations

    0.2.0 • Public • Published


    Bundle minified size Bundle minified and gzipped size

    Types and type-safe functions for JSON.

    • 📦 Distributions in ESM, CommonJS, UMD and UMD minified formats.

    • Lightweight:

      • Weighs less than 0.2KB (min + gzip).
      • Tree-shakeable.
      • Side-effects free.
    • 🔋 Batteries included:

      • No dependencies.
      • Its not based on newer browser's APIs or es2015+ features.
    • 🏷 Safe:

      • JSDocs and type declarations for IDEs and editor's autocomplete/intellisense.
      • Made with TypeScript as strict as possible.
      • Unit tests with AVA (types was also tested).


    This library is published in the NPM registry and can be installed using any compatible package manager.

    npm install @bitty/json --save
    # For Yarn, use the command below.
    yarn add @bitty/json

    Installation from CDN

    This module has a UMD bundle available through JSDelivr and Unpkg CDNs.

    <!-- For UNPKG use the code below. -->
    <script src=""></script>
    <!-- For JSDelivr use the code below. -->
    <script src=""></script>
      // UMD module is exposed through the "Json" global object.
      //=> "[Object: Json]"
      console.log(Json.toJson({ name: 'Carlos Marcos' }, 0));
      //=> "{\"name\":\"Carlos Marcos\"}"

    Getting Stated

    This module named exports functions and types to type-safely handle JSON.

    import { JsonObject, toJson } from '@bitty/json';
    const sendJson = <T extends JsonObject = JsonObject>(obj: T) => {
      const json = toJson(obj);
      // ...
    sendJson<{ names: Set<string> }>({ ... });
    //=> ❌ Type 'Set<string>' is not assignable to type 'Json'.
    sendJson<{ names: string[] }>({ ... });
    //=> ✅



    An array of Json values.

    import { JsonArray } from '@bitty/json';
    const answers: JsonArray = [false, 'Okay', null, { color: '#fff' }, [0,3]];


    An object whose property keys are strings and values are Json values.

    import { JsonObject } from '@bitty/json';
    const response: JsonObject = {
      id: 36,
      association: null,
      colors: [{color: '#00f'}, {color: '#d7a'}],
      isDisabled: true


    A union of null, boolean, number, string, JsonArray and JsonObject types.

    import { Json } from '@bitty/json';
    const response: Json = {
      latest: undefined, // ❌ Type 'undefined' is not assignable to type 'Json'.
      current: [
          name: 'Orange',
          color: '#ff8721',
          score: 2871,
          disabled: true,


    Converts a valid JSON string into a value, whose type that extends Json.

    import { parseJson } from '@bitty/json';
    type User = {
      name: string;
    const user = parseJson<User>('{"name":"Carlos Marcos"}');


    Converts a value, whose type extends Json, to value to JSON string.

    import { toJson } from '@bitty/json';
    type User = {
      name: string;
    const user = toJson<User>({
      name: 'Carlos Marcos'
    }, 0);
    //=> "{\"name\":\"Carlos Marcos\"}"


    Released under MIT License.


    npm i @bitty/json

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    • vitorluizc
    • bitty