Showing the different types of for loops

for-loop-types-in-es6.js

(()=>{
    const myFriends = [
        { name: "Bob", age: 20},
        { name: "Jane", age: 18},
        { name: "Mary", age: 16},
    ];

    const checkAges = (friends, ages) => {
        ages.forEach((age, i) => {
            const friendsAge = friends[i].age;
            if(friendsAge !== age){
                throw new Error(`Wrong age:{age} at index: ${i}. ${friendsAge} !== ${age}`); 
            }
        });
    }

    const forLoop = (friends) => {
        const ages = [];

        for(let i = 0; i < friends.length; i++){
            ages.push( friends[i].age );
        }

        return ages; 
    };

    const forInLoop = (friends) => {
        const ages = [];

        for(let i in friends ){
            ages.push( friends[i].age );
        }

        return ages; 
    };

    const forOfLoop = (friends) => {
        const ages = [];

        for(let friend of friends ){
            ages.push( friend.age );
        }

        return ages; 
    };

    const forEachLoop = (friends) => {
        const ages = [];

        friends.forEach( friend => {
            ages.push( friend.age );
        });

        return ages; 
    };

    checkAges( myFriends, forLoop(myFriends) );

    checkAges( myFriends, forInLoop(myFriends) );

    checkAges( myFriends, forOfLoop(myFriends) );

    checkAges( myFriends, forEachLoop(myFriends) );
  
   console.log("Ages check out good");
})();