1. ES5 features

   • Explain array methods(map, filter, some, every, reduce, reduceRight, forEach)

     What does this code do?

     emailsString.split(/[,;\s]+/).every(email=>isEmail(email));

     Rewrite it with .some() method

   • Object methods

     • Describe property attributes and Object.defineProperty, Object.getOwnPropertyDescriptor methods

       Write method join:

       vara={a: 1,b: 2,c: 3};a.join()// output: a,b,c

       // possible solution:Object.defineProperty(Object.prototype,'join',{value(){returnObject.keys(this).join(',');},enumerable: false});

     • Explain difference between Object.keys and Object.getOwnPropertyNames:

       vara={q: 1};Object.defineProperty(a,'xxx',{value: 'yyy',enumerable: false});Object.keys(a);// what it returns? Object.getOwnPropertyNames(a);// what it returns? 

     • Setters and Getters

   • Strict mode restrictions

     • Global scope restrictions

     (function(){"use strict";x=100;})();

2. Closures

3. Context

4. Scope

   • What is the result of:

   Object.prototype.x=10;vary=20;(function(){console.log(x,y);})();

5. Write function "reverse" for objects (have to work as for arrays)

   // possible solutionfunctionreverse(obj){returnObject.keys(obj).reverse().reduce((res,i)=>{res[i]=obj[i];returnres;},{});}

6. Write function "pop" for objects (have to work as for arrays)

   // possible solutionfunctionpop(obj){varkeys=Object.keys(obj);if(!keys.length)return;varkey=keys[keys.length-1],val=obj[key];deleteobj[key];returnval;}