sth-larp / TypedJSON

Typed JSON parsing and serializing for TypeScript that preserves type information.

Author's note, please read if incorporating TypedJSON into a serious application:

TypedJSON is currently an experimental release and is not guaranteed to satisfy all use-cases reliably.

The upcoming update is a major update to v1.0.0, and an almost complete rehaul of the TypedJSON API with significant improvements over the initial release, based on significant amounts of feedback and practical use. This version is coming with a massive test-suite to start going towards more serious application possibilities, as many aspects of TypedJSON were found suitable for enterprise-grade use.

Since numerous unnecessary features and decisions will be abandoned, this update will introduce breaking changes, of which the most notable will be:

• Properties of type Array, Map, Set will use JsonArrayMember, JsonMapMember, and JsonSetMember (respectively, and yes, support for these new ES6 collection types is finally coming)
• JsonMember will no longer support Array
• Configurable type-hint key replaced with configurable type-resolver and type-emitter callbacks (although with an identical default behavior)

Why the breaking changes?

1. Because I feel the syntax of TypedJSON is so lightweight that, at this stage, it would be absolutely trivial to incorporate these changes into virtually any project
2. Because it is better to do a hard-switch to a (subjectively) better API as early on as possible, without the burden of legacy code

This update is live as soon as all integration testing is done, anticipated in March, 2017. The main principle of TypedJSON is not subject to change, the API is permanently locked to a decorator-based approach.

Notable non-breaking changes in this update will be:

• Support for ES6 Set and ES6 Map (although not for WeakMap and WeakSet)
• Support for all typed arrays (such as Float32Array and Uint8Array)
• Meaningful error messages and configurable error handler callback
• Known-types can be acquired through static methods of decorated classes (as Function[])

TypedJSON

Strong-typed JSON parsing and serializing for TypeScript with decorators. Parse JSON into actual class instances. Recommended (but not required) to be used with ReflectDecorators, a prototype for an ES7 Reflection API for Decorator Metadata.

• Parse regular JSON to typed class instances, safely
• Seamlessly integrate into existing code with decorators, ultra-lightweight syntax

Install & Use

npm install typedjson-npm
typings install npm:typedjson-npm

1. Snap the @JsonObject decorator on a class
2. Snap the @JsonMember decorator on properties which should be serialized and deserialized
3. Parse and stringify with the TypedJSON class

@JsonObject
class Person {
    @JsonMember
    firstName: string;

    @JsonMember
    lastName: string;

    public getFullname() {
        return this.firstName + " " + this.lastName;
    }
}

var person = TypedJSON.parse('{ "firstName": "John", "lastName": "Doe" }', Person);

person instanceof Person; // true
person.getFullname(); // "John Doe"

If you choose to omit using ReflectDecorators, the class (constructor function) of each @JsonMember decorated property must be specified manually through the type setting, for example:

@JsonMember({ type: String })
firstName: string;

Learn more about decorators in TypeScript

Documentation

• API reference

License

TypedJSON is licensed under the MIT License.