As a beginner in TypeScript and currently exploring its integration with AngularJS, I am facing a particular issue where the compiler is not detecting an error.
In Angular, a resource provider typically includes a get() method that returns an instance of a type parameter, denoted as T. This method has multiple overloads and can accept parameters such as params or data, along with success and error handlers defined by interfaces like:
interface IResourceSuccessCallbackFunction<T> {
(value: T, responseHeaders: Array<string>): void;
}
interface IResourceErrorCallbackFunction {
(httpResponse: string): void;
}
To define these overloads for the get function, I referred to the declaration file available at DefinitelyTyped. Here are the different variations I came up with:
interface IResourceClass<T> {
get(): T;
get(dataOrParams: any): T;
get(dataOrParams: any, success: IResourceSuccessCallbackFunction<T>): T;
get(success: IResourceSuccessCallbackFunction<T>, error?: IResourceErrorCallbackFunction): T;
get(params: any, data: any, success?: IResourceSuccessCallbackFunction<T>, error?: IResourceErrorCallbackFunction): T;
}
The issue arises when utilizing these definitions in practice. For example:
var resourceService: IResourceClass<number> = null;
var res1 = resourceService.get({ id: 1000 }, function() {
console.log("fail");
});
var res2 = resourceService.get(function(p: Phone) {
console.log(p);
}, function() {
console.log("fail");
});
In both cases, incorrect arguments are being passed to the functions, yet the calls compile successfully due to the nature of the overloaded variant structure. Is there a way to enhance these definitions to capture and flag such errors during compilation?
I'm seeking a solution that can enforce stricter typing rules or introduce alternative techniques to prevent misuse of the overloaded functions. Any suggestions on achieving this would be greatly appreciated.