Can not use nested object method in expression for binding

Description

class ViewModel extends Observable {
    public obj = {
        fun: function () {
            return "It's fun()"
        }
    }
}

const vm = new ViewModel();

<Label text="{{ obj.fun() }}"/>

Binding: Run-time error occured in file: undefined at line: undefined and column: undefined

Contributor guide

Tech stack

javascripttypescriptandroid

Domain

frontend

Issue type

bug

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

1-3 hours

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

stale

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

clear

Prerequisites

Basic knowledge of NativeScriptFamiliarity with data binding expressions

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

50

Research direction

The issue is about nested object method calls not working in binding expressions (e.g., `{{ obj.fun() }}`). To fix, investigate the binding expression parser in NativeScript core, likely in files like `src/ui/builder/binding parser.ts` or similar. Check how property access and function calls are handled in expressions. The error occurs at runtime, so the expression evaluation logic needs to support chained method calls on nested objects. Look at existing tests for binding expressions to understand expected behavior.