Check array of objects for a specific property value

Question

I'm creating a small program where I have a page with two input fields and a user can enter their name and the number of calories they've eaten today. After a person enters their data, I want to display it alongside other people's data in a list sorted by total calories.

I also want that person to be able to re-enter their name and additional calories and have it update their total calories (as opposed to creating another entry with their name and most recent calorie amount).

I am assigning the input values to variables, using those to create a new Person object, then pushing that object to an array.

How can I test to see if the array contains a Person object with a name that already exists? My test isn't recognizing names that have already been submitted. If a person's name has already been entered, I'd like to update their total calories instead of creating a new Person object.

My javascript code:

(function () {
    "use strict";

    /* Person object constructor */
    function Person(name, calories) { 
        this.name = name;
        this.calories = calories;
    }

    function addToList() {
        var name = document.getElementById('name').value;
        var calories = document.getElementById('calories').value;

        /* 
            Check to see if list already contains person's name
            If yes, update their calorie amount.
            If not, create a new player and add them to the list.
         */

        for (var i = 0; i < list.length; i++) {
            if (list[i] === name) {
                alert('This person already exists.');
            } else {
                var newPerson = new Person(name, calories);
                list.push(newPerson);
            }   
        }
    }

    var list = [];
    $('#add').click(addToList);

})();

Answer 1

Your list is a list of Person (if rankings.push is meant to be list.push) so when you are doing (list[i] === name) that is trying to compare a Person object to a string literal. Try doing (list[i].name.toLowerCase() === name.toLowerCase())

Answer 2

It looks like you're storing names inside of the array list, however these names are never being ADDED to list. Instead you appear to be using another array called rankings.

rankings.push(newPerson);
list.push(name);

And since you already have an array that stores people, rankings, maybe you should iterate over that?

var foundPerson = false;
for (var i = 0; i < rankings.length; i++) {
    if (rankings[i].name === name) {
        alert('This person already exists.');

        // do your update
        rankings[i].calories = calories;

        // set flag so we know we actually found a person
        foundPerson = true;
        break;
    } 
}

// if no person found, add new person
if (!foundPerson) {
    var newPlayer = new Person(name, calories);
    rankings.push(newPerson);
}