TypeScriptでの構造的部分型の説明をざっくりやった

StructualSubtyping.ts

interface A {
  hoge(str:string): string;
}

interface B {
	hoge(str:string): string;
}

class AImpl {
	hoge(str) {
		return str + "&" + str;
	}
}

var fn = function(b: B) {
	alert(b.hoge("test"));
}

fn(new AImpl());

var aImpl = {
	hoge:(str:string):string => { return "triple:" + str + str + str; }
};
fn(aImpl);