打字稿从打字扩展类

Question

I have a library which I'm building with grunt. There's a class named SearchResult which is propertly exported in my 'd.ts' file:

declare module my.module {
    export class SearchResult {
        id?: string;
        object_type: string;
        item?: any;
        type?: string;
    }
}

And it's compiled to this:

357:[function(require,module,exports){
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
var SearchResult = (function () {
    function SearchResult() {
    }
    return SearchResult;
}());
exports.SearchResult = SearchResult;
},{}]

But when I import this file using reference and trying to extend this class like that:

export class SearchResultChecked extends my.module.SearchResult {
    checked?: boolean;
}

I've got a runtime error:

Uncaught TypeError: Object prototype may only be an Object or null: undefined
    at setPrototypeOf (<anonymous>)
    at __extends (_prelude.js:1)

There's many similar problems, but they're not the same.

tsc -v : 3.0.1

UPD : it lloks like I can't extend class which is not last defined in my library. Looking for solutions.

Answer 1

.d.ts files are not emitted, they don't produce any code, and only exist on the type level (conceptually, at the linker level).

Code written in .d.ts files never makes it to runtime, it just tells TypeScript "assume that this class/enum/whatever is there, even though you aren't going to emit JS code about it"

If you want a class to actually exist in runtime, you will need to actually export it from an actual .ts file, or import a library that exposes the class.