Have interface extend string functionality
I'm using these tools together: TypeScript Gulp Gulp-Inject I'm trying to do the following: module My { interface IGulpInjectable extends string { // << Problem here! [gulp_inject: string] : string; } export class Cache { private items: { [key: string] : IGulpInjectable }; constructor() { this.items = { "item1": { gulp_inject: "file1.html" }, "item2": { gulp_inject: "file2.html" } } } getItem(key: string){ return this.items[key].trim(); } } } What gulp-inject does is replace { gulp_inject: "x.html" } with a string containing the file contents. This is why I want to have IGulpInjectable extend