Question

I wrote some js:

var folersTreeMgr = {

    sendDeleteFolderRequestAndUpdateFoldersTree: function () {
       ...

        } else {
            createAjaxRequest("Manager/DeleteLocation", {
                'locationId': folder_minimal_descriptor.locationId
            }).done(function (isSucceeded) {

                if (isSucceeded) {

                    folersTreeMgr.deleteFolderInFoldersTree(); // works
                    this.deleteFolderInFoldersTree(); // doesn't work
                    deleteFolderInFoldersTree(); // doesn't work
                }

                //TODO: else: error
            });
        }
    },


    deleteFolderInFoldersTree: function () {
        $("#jstree").jstree("remove", null);
    }
};

why do I get “missing function” error

Answer 1

Because you’re using this inside a callback, where it has different meaning.

You can referene the outer this in a variable, then use that in the callback.

var folersTreeMgr = {

    sendDeleteFolderRequestAndUpdateFoldersTree: function () {

       var self = this;  // cache it

       ...

        } else {
            createAjaxRequest("Manager/DeleteLocation", {
                'locationId': folder_minimal_descriptor.locationId
            }).done(function (isSucceeded) {
                if (isSucceeded) {
                   self.deleteFolderInFoldersTree(); // works
                }
            });
        }
    },
    deleteFolderInFoldersTree: function () {
        $("#jstree").jstree("remove", null);
    }
};

---

Or use $.proxy to keep the this value…

createAjaxRequest("Manager/DeleteLocation", {
    'locationId': folder_minimal_descriptor.locationId
}).done( $.proxy(function (isSucceeded) {
    if (isSucceeded) {
       this.deleteFolderInFoldersTree(); // works
    }
},this) );

This’ll return a function that has the second argument to $.proxy bound to the function passed as the first argument.