Toy hook example for medium article.

hook.js

class Hook {
    constructor(){
        this.hookedFunctions = [];
    }

    hookFunction(functionToHook){
        this.hookedFunctions.push(functionToHook);
    }

    callHook(){
        this.hookedFunctions.forEach(hookedFunction => hookedFunction());
    }
}

var hook = new Hook();
hook.hookFunction(() => console.log("hello"))
hook.hookFunction(() => console.log("world"))
hook.callHook();