Question

I’m very new to JavaScript and I need some advice on why I am getting an error message that states this.node is undefined.

What I have is a app built on ExtJs using the MVC architect. In my Controller, I have developed a layout containing a tree and a grid. In the tree, there are parent nodes that can be added by clicking a New button and its method works perfectly.

However the method that will update a record by id from my database using the same form that is used to insert a record is generating a message stating the this.node is undefined.

This is my code for the Edit handler:

handleBtnEdit: function (btn, ev, eOpts) {
    console.log(this);
    var id = parseInt(this.node.get("id")), rec = this.app.getStore("ProblemRequirements").getById(id);
    this.launchForm(rec);
}, 
handleBtnAdd: function (btn, ev, eOpts) {
    var rec = Ext.create("SPOT.model.ProblemRequirement");
    this.launchForm(rec);
}, 
handleBtnSave: function (btn, eOpts) {
    var win = btn.up("window"), pnl = win.down("form"), frm = pnl.getForm(), grid = pnl.down("grid"), store = grid.getStore(), rec = frm.getRecord();
    if (frm.isValid()) {
        rec.set(frm.getValues());
        win.setLoading("Saving, please wait...");
        rec.save({
            callback : function(rec, operation) {
                if (operation.success) {
                    win.close();
                    this.getStore("ProblemRequirements").load();
                    this.playMsg("Problem requirement successfully " + (operation.action === "update" ? "updated" : "created" ) + ".");
                } else {
                    win.setLoading(false);
                    Ext.Msg.alert("Error!", operation.error[0].ERROR);
                }
            },
            scope : this
        });
    }
}, 
launchForm: function (rec) {
    Ext.create("Ext.window.Window", {
        buttons : [{
            handler : this.handleBtnSave,
            scope : this,
            text : "Save"
        }, {
            handler : this.handleBtnCancel,
            scope : this,
            text : "Cancel"
        }],
        closable : false,
        draggable : false,
        iconCls : (rec.phantom ? "icon-add" : "icon-edit"),
        items : [{
            listeners : {
                afterrender : {
                    fn : function(pnl, eOpts) {
                        pnl.getForm().loadRecord(rec);
                    },
                    scope : rec
                }
            },
            xtype : "problemrequirementForm"
        }],

        modal : true,
        resizable : false,
        title : (rec.phantom ? "Create a New" : "Edit") + " Problem Requirement",
        width : 500
    }).show();
},

Answer 1

Replace your handleBtnEdit with this version and copy paste your console log.

handleBtnEdit: function (btn, ev, eOpts) {
    console.log("-- Start of handleBtnEdit --");

    console.log(btn);
    console.log("-- 1 --");

    console.log(ev);
    console.log("-- 2 --");

    console.log(this);
    console.log("-- 3 --");

    console.log(this.getAttribute("id"));
    console.log("-- 4 --");

    console.log(this.node);
    console.log("-- 5 --");

    //var id = parseInt(this.node.get("id"));
    //var rec = this.app.getStore("ProblemRequirements").getById(id);
    //this.launchForm(rec);
}, 

Also, add the code which calls handleBtnEdit.

Update

Console log:

-- Start of handleBtnEdit -- 
btn :: Object { disabled= false , iconCls= "icon-edit" , id= "btn-edit" , more...} 
-- 1 -- 
ev :: Object { browserEvent=Event click, type= "click" , button= 0 , more...} 
-- 2 -- 
this :: Object { application={...}, id= "ProblemRequirements" , hasListeners={...}, more...} 
-- 3 --

So, the argument passed in a button with id= "btn-edit".
this seems to be an Object with id= "ProblemRequirements".

Update 2

As there is no node inside this and the id of this doesn’t seem to be one we need, try this code:

handleBtnEdit: function (btn, ev, eOpts) {
    var id = parseInt(btn.id);
    var rec = this.application.getStore("ProblemRequirements").getById(id);
    this.launchForm(rec);
},