I want to make sure that an interface member of type string is a formally valid URL. I could declare a member as URL but I cannot assign it a string that is a valid URL.
interface test {
myurl: URL;
}
var a : test;
a.myurl = "http://www.google.ch"
When compiling I get:
Type 'string' is not assignable to type 'URL'.
Do I have to use decorators for my task (https://www.typescriptlang.org/docs/handbook/decorators.html)?
And what is URL good for?
I am using typescript 1.8.10
Answer
AFAICT, URL is a typescript "built-in" feature, based on the WhatWG Url specifications. The linked to page has both rationale and examples.
In short it offers a structured way of using urls while making sure that they are valid. It will throw errors when attempting to create invalid urls.
Typescript has the according type-definitions set as follows (as of typescript 2.1.5): in node_modules/typescript/lib/lib.es6.d.ts:
interface URL {
hash: string;
host: string;
hostname: string;
href: string;
readonly origin: string;
password: string;
pathname: string;
port: string;
protocol: string;
search: string;
username: string;
toString(): string;
}
declare var URL: {
prototype: URL;
new(url: string, base?: string): URL;
createObjectURL(object: any, options?: ObjectURLOptions): string;
revokeObjectURL(url: string): void;
}
For your use-case you should be able to use it like this:
a.myurl = new URL("http://www.google.ch");
More constructors, samples and explanations can be found in the WhatWG Url specifications.