Function to add and replace items in observable array

Question

Im trying to write a function that 1. adds an item to an observable array and 2. replaces the item if it already exists in the array

self.addNotification = function (name, availability, note) {
    //see if we already have a line for this product
    var matchingItem = self.notifications.indexOf(name);

    if (matchingItem !== undefined) {
        self.notifications.replace(self.notifications()[index(matchingItem)],
            new Notification(self, name, availability, note));
    }
    else {
        self.notifications.push(new Notification(self, name, availability, note));
    }
};

What am I doing wrong?

Regards Anders

Xitalogy · Accepted Answer · 2012-10-22 22:16:38Z

Here is my answer: fiddle

Hit F12 in Chrome or use FireBug in FireFox to see console log output.

var notifications = {
    notifs: [],
    updateNotifications: function(notification) {
        'use strict';

        var matchIndex;

        for (matchIndex = 0; matchIndex < this.notifs.length; matchIndex += 1) {
            if (this.notifs[matchIndex].name === notification.name) {
                break;
            }
        }
        if (matchIndex < this.notifs.length) {
            this.notifs.splice(matchIndex, 1, notification);
        } else {
            this.notifs.push(notification);
        }
    }
};

notifications.updateNotifications({
    name: 'John',
    available: false,
    note: "Huzzah!"
});
notifications.updateNotifications({
    name: 'Jane',
    available: true,
    note: "Shazam!"
});
notifications.updateNotifications({
    name: 'Jack',
    available: true,
    note: "Bonzai!"
});
notifications.updateNotifications({
    name: 'Jane',
    available: false,
    note: "Redone!"
});
console.log(notifications);

jAndy · Accepted Answer · 2012-10-22 21:18:25Z

1

Well, Array.prototype.indexOf never returns undefined. Its either -1 (not found) or any number starting with 0 for the array index.

answered Oct 22, 2012 at 21:18

jAndy

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1 Comment

mupersan82 Over a year ago

Okay thanks, I have changed undefined to -1... But it just keeps adding items to the array.

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