How can I easily create a strongly typed object from an anonymous object in TypeScript?

Question

I have some JSON containing anonymous objects coming to my client-side. Is there some built-in mechanism or external library for converting these anonymous objects into strongly-typed TypeScript objects? Is there something like AutoMapper for doing this?

My objects are complex types, with complex types as properties.

Answer 1

Get some sample data and place it in a .ts file:

var people = [
    {
        "name": "bob", "height": 150, "pets": [{ "name": "spot", "species": "dog" }]
    },
    {
        "name": "jane", "height": 142, "pets": [{ "name": "lucy", "species": "cat" }]
    }
];

Run tsc --declaration yourFile.ts

Now you'll have yourFile.d.ts:

declare var people: {
    "name": string;
    "height": number;
    "pets": {
        "name": string;
        "species": string;
    }[];
}[];

Replace declare var people: with interface Person, remove the trailing [], and (optionally) remove the quotes:

interface Person {
    name: string;
    height: number;
    pets: {
        name: string;
        species: string;
    }[];
}