How do I remove the objects I want from an array and add them to another array using .forEach?

Question

This is a coding challenge I'm working on and can't seem to grasp what I need to do. Not sure if I am even going in the right direction.

Here is the instructions: Here we have an array called people. Some of them are our friends and some are not. 1. Create an empty array called friends. 2. Using .forEach, loop over people and add those that are our friend to the empty friends array.

Here is the provided code:

var people = [
  {name: "Landy",friend: true},
  {name: "Corey",friend: true},
  {name: "Ted",friend: false},
  {name: "Sperry",friend: true},
  {name: "Bill",friend: false}
];

My code so far:

var friends = [];
people.forEach(function(people){
  if (people === true) {
    return name;
  } else {
    // 
  }
});

forEach doesn't do anything with the return value of the function, what's the point of return name;? — Barmar
– Barmar, Commented Nov 16, 2017 at 0:27

Derek 朕會功夫 · Accepted Answer · 2017-11-16 00:09:32Z

2

One possible solution would be

var friends = [];
people.forEach(p => {
    if(p.friend)            // if person is a friend
        friends.push(p);    // push it to our friends array
});

// or

people.forEach(p => p.friend && friends.push(p));  // short-circuiting

We can also do this if we don't have to use .forEach

// use the key ".friend" as the condition
var friends = people.filter(p => p.friend);

Traditional way of doing it

var friends = [];
for(var i = 0; i < people.length; i++){
    p = people[i];          // get i-th people
    if(p.friend)            // if person is a friend
        friends.push(p);    // push it to our friends array
});

Example:

var people = [
  {name: "Landy",friend: true},
  {name: "Corey",friend: true},
  {name: "Ted", friend: false},
  {name: "Sperry", friend: true},
  {name: "Bill",friend: false}
 ];
 
var friends = [];
people.forEach(p => {
  if(p.friend)
    friends.push(p);
});

console.log(friends);

edited Nov 16, 2017 at 0:09

answered Nov 15, 2017 at 23:57

Derek 朕會功夫

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3 Comments

batman091716 Over a year ago

Maybe there is something wrong with the site I am doing it through.

batman091716 Over a year ago

Actually it does also say this in the instructions: Only add the persons name to the friends array (Should look something like this ["name", "name", "name"])

Derek 朕會功夫 Over a year ago

@batman091716 If that's the case, push p.name instead of just p. But the most important thing here is that you fully understand the code.

AngelSalazar · Accepted Answer · 2017-11-15 23:57:00Z

2

var friends = [];
people.forEach(function(person){
  if (person.friend) friends.push(person)
});

answered Nov 15, 2017 at 23:57

AngelSalazar

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Comments

ktilcu · Accepted Answer · 2017-11-16 00:14:10Z

0

I would do this using #Array.prototype.filter. It's the easiest. You can also use #Array.prototype.map to transform "persons" to "names". Click the button to run the code below and see for yourself.

var people = [
  {name: "Landy",friend: true},
  {name: "Corey",friend: true},
  {name: "Ted",friend: false},
  {name: "Sperry",friend: true},
  {name: "Bill",friend: false}
];

var friends = people
  // only keep the people that are friends
  .filter(person => person.friend)
  // transform a person to a name
  .map(person => person.name);
console.log(friends)

answered Nov 16, 2017 at 0:14

ktilcu

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Comments

Lolu Omosewo · Accepted Answer · 2017-11-16 00:07:26Z

-2

This is a quick solution using $.grep();

var friends=$.grep(people,function(o){
                                  return o.friend;
                                     });

$.grep() returns array of object passed into the callback function that returns true

answered Nov 16, 2017 at 0:07

Lolu Omosewo

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