.computejsondifference doesnot exists on type model

GoJS
1

i m working on an angular 6 diagram i made the same diagram in core js and it worked flawlessly but now i m getting an error on .compute json difference function

var savedModel = go.Model.fromJson({ “class”: “go.TreeModel”,“nodeDataArray”:this.tree_data});
//var savedModel = JSON.stringify(this.tree_data);
console.log(savedModel.nodeDataArray);
console.log(this.diagram.model.nodeDataArray);
element2.innerHTML = savedModel.computeJsonDifference(this.diagram.model);

incremental1
incremental1.PNG801×251 20.5 KB

it says that this function doesn’t exist on type model

2

It’s an undocumented method that is not declared in the go.d.ts file. But it is defined on Model. For now you can either modify the go.d.ts file or you can call it using a string name and maybe some TypeScript casts.

3

what exactly does this mean
“It’s an undocumented method that is not declared in the go.d.ts file. But it is defined on Model”
and what am i suppose to do i didn’t get it

4 
... = savedModel["computeJsonDifference"](this.diagram.model);