[SOLVED] Check if an object implements an interface at runtime with TypeScript

Issue

I load a JSON configuration file at runtime, and use an interface to define its expected structure:

interface EngineConfig {
    pathplanner?: PathPlannerConfig;
    debug?: DebugConfig;
    ...
}

interface PathPlannerConfig {
    nbMaxIter?: number;
    nbIterPerChunk?: number;
    heuristic?: string;
}

interface DebugConfig {
    logLevel?: number;
}

...

This makes it convenient to access the various properties since I can use autocompletions etc.

Question: is there a way to use this declaration to check the correctness of the file I load? ie that I do not have unexpected properties?

Solution

No.

Currently, types are used only during development and compile time.
The type information is not translated in any way to the compiled
JavaScript code.

From https://stackoverflow.com/a/16016688/318557, as pointed out by @JasonEvans

There is an open issue since Jun 2015 about this in the TypeScript repo: https://github.com/microsoft/TypeScript/issues/3628

Answered By – MasterScrat

Answer Checked By – Jay B. (BugsFixing Admin)