The method xxx is not defined within my ViewModel

Question

The method xxx is not defined within my ViewModel

Why am I encountering an error

Uncaught TypeError: this.createRow is not a function

when constructing the matrixLengthsAvailable array?

The createRow function is defined at the end of my viewmodel...

function TabBuyHarvesterModel() {
    self = this;

    this.selectedEmote = ko.observable('kappa');
    this.matrixLengthsAvailable = ko.observableArray([
        { length: 10, pctDetails: this.createRow(10) /*ko.mapping.fromJS({ rowLength: 10 })*/ }
        //30,
        //60,
        //180,
        //360,
        //720,
            //1440
        ]);

    this.selectEmote = function (emoteClicked) {
        self.selectedEmote(emoteClicked.emote);
    };

    this.createRow = function (rowLength) {
        var ret = new TabBuyHarvesterMatrixRowModel();
        ret.rowLength(rowLength);
        return ret;
    };
}

javascript knockout.js

Answer 1

Answer №1

It is advisable to utilize the 'self' method as suggested and ensure its correct implementation throughout your code. Additionally, make sure to reorganize the order of methods so that 'createRow' is declared prior to its usage.

To view the example, visit: http://jsfiddle.net/oshmn46o/

function TabBuyHarvesterModel() {
var self = this;

self.createRow = function (rowLength) {
    var ret = new TabBuyHarvesterMatrixRowModel();
    ret.rowLength(rowLength);
    return ret;
};

self.selectedEmote = ko.observable('kappa');
self.matrixLengthsAvailable = ko.observableArray([
    { length: 10, pctDetails: self.createRow(10) /*ko.mapping.fromJS({ rowLength: 10 })*/ }
    //30,
    //60,
    //180,
    //360,
    //720,
        //1440
    ]);

self.selectEmote = function (emoteClicked) {
    self.selectedEmote(emoteClicked.emote);
};

}

Answer 2

It is advisable to utilize the 'self' method as suggested and ensure its correct implementation throughout your code. Additionally, make sure to reorganize the order of methods so that 'createRow' is declared prior to its usage.

To view the example, visit: http://jsfiddle.net/oshmn46o/

function TabBuyHarvesterModel() {
var self = this;

self.createRow = function (rowLength) {
    var ret = new TabBuyHarvesterMatrixRowModel();
    ret.rowLength(rowLength);
    return ret;
};

self.selectedEmote = ko.observable('kappa');
self.matrixLengthsAvailable = ko.observableArray([
    { length: 10, pctDetails: self.createRow(10) /*ko.mapping.fromJS({ rowLength: 10 })*/ }
    //30,
    //60,
    //180,
    //360,
    //720,
        //1440
    ]);

self.selectEmote = function (emoteClicked) {
    self.selectedEmote(emoteClicked.emote);
};

}

Answer 3

Answer №2

When utilizing ko.observableArray(), the reference to 'this' in this.createRow will point to the context of the observableArray. It is advisable to replace 'this' with 'self' for clarity and consistency.

Answer 4

When utilizing ko.observableArray(), the reference to 'this' in this.createRow will point to the context of the observableArray. It is advisable to replace 'this' with 'self' for clarity and consistency.

Answer 5

Answer №3

It seems like you're attempting to call the createRow function before it has even been defined. To avoid this issue, make sure to define createRow before matrixLengthsAvailable. A more efficient approach would be to define the createRow method on the prototype of TabBuyHarvesterModel. By doing so, the function will only be declared once, ensuring it is available before any instances of your class are created.

function TabBuyHarvesterModel() {
    ...
}

TabBuyHarvesterModel.prototype.createRow = function (rowLength) {
    var ret = new TabBuyHarvesterMatrixRowModel();
    ret.rowLength(rowLength);
    return ret;
};

Answer 6

It seems like you're attempting to call the createRow function before it has even been defined. To avoid this issue, make sure to define createRow before matrixLengthsAvailable. A more efficient approach would be to define the createRow method on the prototype of TabBuyHarvesterModel. By doing so, the function will only be declared once, ensuring it is available before any instances of your class are created.

function TabBuyHarvesterModel() {
    ...
}

TabBuyHarvesterModel.prototype.createRow = function (rowLength) {
    var ret = new TabBuyHarvesterMatrixRowModel();
    ret.rowLength(rowLength);
    return ret;
};

Answer 7

Answer №4

It is recommended to only reference the function createRow from within the scope of TabBuyHarvesterModel. By making it a regular function, you can avoid the need to define createRow before the observable matrixLengthsAvailable. JavaScript automatically hoists functions to the top of a closure, even if they are not initially defined at the beginning of the closure:

function TabBuyHarvesterModel() {
    self = this;

    this.selectedEmote = ko.observable('kappa');
    this.matrixLengthsAvailable = ko.observableArray([
        { length: 10, pctDetails: createRow(10) /*ko.mapping.fromJS({ rowLength: 10 })*/ }
        //30,
        //60,
        //180,
        //360,
        //720,
            //1440
        ]);

    this.selectEmote = function (emoteClicked) {
        self.selectedEmote(emoteClicked.emote);
    };

    function createRow(rowLength) {
        var ret = new TabBuyHarvesterMatrixRowModel();
        ret.rowLength(rowLength);
        return ret;
    }
}

Answer 8

It is recommended to only reference the function createRow from within the scope of TabBuyHarvesterModel. By making it a regular function, you can avoid the need to define createRow before the observable matrixLengthsAvailable. JavaScript automatically hoists functions to the top of a closure, even if they are not initially defined at the beginning of the closure:

function TabBuyHarvesterModel() {
    self = this;

    this.selectedEmote = ko.observable('kappa');
    this.matrixLengthsAvailable = ko.observableArray([
        { length: 10, pctDetails: createRow(10) /*ko.mapping.fromJS({ rowLength: 10 })*/ }
        //30,
        //60,
        //180,
        //360,
        //720,
            //1440
        ]);

    this.selectEmote = function (emoteClicked) {
        self.selectedEmote(emoteClicked.emote);
    };

    function createRow(rowLength) {
        var ret = new TabBuyHarvesterMatrixRowModel();
        ret.rowLength(rowLength);
        return ret;
    }
}

The method xxx is not defined within my ViewModel

Answer №1

Answer №2

Answer №3

Answer №4

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