If-else inside a for loop not working - Javascript

Question

I have an array "contacts" with a few properties. My function uses a for to check if the firstName property of each contact matches the name parameter of my function, if it does, it checks if such contact has a property that matches the prop parameter (an if inside the previous if). Both "ifs" have corresponding "elses": "no such property", "not such contact".

Code is very simple actually:

var contacts = [
  {
    "firstName": "Akira",
    "lastName": "Laine",
    "number": "0543236543",
    "likes": ["Pizza", "Coding", "Brownie Points"]
  },
  {
    "firstName": "Harry",
    "lastName": "Potter",
    "number": "0994372684",
    "likes": ["Hogwarts", "Magic", "Hagrid"]
  },
  {
    "firstName": "Kristian",
    "lastName": "Vos",
    "number": "unknown",
    "likes": ["JavaScript", "Gaming", "Foxes"]
  }
];


function lookUpProfile(name, prop) {

  for (var i = 0; i < contacts.length; i++) {

    if (contacts[i].firstName === name) {

      if (contacts[i].hasOwnProperty(prop)) {
        return contacts[i][prop];
      }
      else {
        return "No such property";
      }
    }
    else {
      return "No such contact";}
  }  
}

console.log(lookUpProfile("Harry", "likes"));

Following lines work perfectly:

console.log(lookUpProfile("Akira", "likes"));
console.log(lookUpProfile("Akira", "lala"));

Now, If I put any other firsNames of the rest of the elements:

console.log(lookUpProfile("Harry", "likes"));
console.log(lookUpProfile("Kristian", "likes"));

it returns "No such contact".... :/

you are using return within for loop, which will interrupt your for loop when no match is found. — random
– random, Commented Jul 7, 2019 at 5:12

Jack Bashford · Accepted Answer · 2019-07-07 05:14:12Z

1

That's because you're returning No such contact in the first loop iteration. Place this at the bottom of your function after the loop as a catch-all.

var contacts=[{"firstName":"Akira","lastName":"Laine","number":"0543236543","likes":["Pizza","Coding","Brownie Points"]},{"firstName":"Harry","lastName":"Potter","number":"0994372684","likes":["Hogwarts","Magic","Hagrid"]},{"firstName":"Kristian","lastName":"Vos","number":"unknown","likes":["JavaScript","Gaming","Foxes"]}]

function lookUpProfile(name, prop) {

  for (var i = 0; i < contacts.length; i++) {

    if (contacts[i].firstName === name) {

      if (contacts[i].hasOwnProperty(prop)) {
        return contacts[i][prop];
      } else {
        return "No such property";
      }
    }
  }
  return "No such contact";
}

console.log(lookUpProfile("Harry", "likes"));
console.log(lookUpProfile("Kristian", "likes"));
console.log(lookUpProfile("Made Up Person", "likes"));
console.log(lookUpProfile("Akira", "Made Up Property"));

answered Jul 7, 2019 at 5:14

Jack Bashford

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3 Comments

Ana Over a year ago

Mmm but I don't understand... why outside..? Why can't it be inside the else of the first if... ? Isn't that logic? And why the for stops there.. I can't code if i don't understand the way it works..

Jack Bashford Over a year ago

return exits the function - so if the first contact isn't the person you're looking for, then it'll flow to the if, right? You were returning - and that will exit the function with the message No such contact. Does that make sense @Ana?

Ana Over a year ago

Ohhh I seee, Guess I need a lot to learn yet :D Thank u very much!

Code Maniac · Accepted Answer · 2019-07-07 05:21:51Z

0

In your current code if the first element of array doesn't match the current passed name than it goes to else block and return "No such contact" ( eventually just checks first element only )

You're returning wrongly from else block in for loop, you need to place it out of loop

var contacts = var contacts=[{"firstName":"Akira","lastName":"Laine","number":"0543236543","likes":["Pizza","Coding","Brownie Points"]},{"firstName":"Harry","lastName":"Potter","number":"0994372684","likes":["Hogwarts","Magic","Hagrid"]},{"firstName":"Kristian","lastName":"Vos","number":"unknown","likes":["JavaScript","Gaming","Foxes"]}]

function lookUpProfile(name, prop) {
  for (var i = 0; i < contacts.length; i++) {
    if (contacts[i].firstName === name) {
      if (contacts[i].hasOwnProperty(prop)) {
        return contacts[i][prop];
      } else {
        return "No such property";
      }
    }
  }
  return "No such contact";
}

console.log(lookUpProfile("Harry", "likes"));

edited Jul 7, 2019 at 5:21

answered Jul 7, 2019 at 5:15

Code Maniac

37.9k5 gold badges44 silver badges65 bronze badges

3 Comments

Ana Over a year ago

Mmm but I don't understand... why outside..? Why can't it be inside the else of the first if... ? Isn't that logic? And why the for stops there.. I can't code if i don't understand the way it works..

Code Maniac Over a year ago

@Ana it is outside as if none of the contact matches in loop then only return no contact found, if there's any matching contact your function don't event come to this line

Code Maniac Over a year ago

@Ana

In your current code if the first element of array doesn't match the current passed name than it goes to else block and return "No such contact" ( eventually just checks first element only )

this line explains why you need to place it out of loop

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