Expression Syntax

VSchema uses syntax to embed JavaScript expressions in strings.

Basic Syntax

Simple Expressions

{ "children": "{{ count }}" }
{ "children": "{{ user.name }}" }
{ "children": "{{ items[0] }}" }

Text Interpolation

{ "children": "Hello, {{ name }}! Welcome to {{ siteName }}" }

Arithmetic Expressions

{ "children": "{{ count + 1 }}" }
{ "children": "{{ price * quantity }}" }

Ternary Expressions

{ "children": "{{ isVip ? 'VIP User' : 'Regular User' }}" }
{ "props": { "class": "{{ active ? 'active' : '' }}" } }

In Props

Dynamic Class

{ "props": { "class": "{{ isActive ? 'btn-active' : 'btn-normal' }}" } }

Dynamic Style

{
  "props": {
    "style": {
      "color": "{{ textColor }}",
      "fontSize": "{{ fontSize }}px"
    }
  }
}

Available Variables

Variable	Description	Example
state	Current state object	state.count
computed	Computed properties	computed.total
$event	Event object (in event handlers)	$event.target.value
$response	API response (in fetch then)	$response.data
$error	Error object (in catch)	$error.message
$methods	Injected external methods	$methods.login()

Security Restrictions

For security, the expression evaluator prohibits:

• eval, Function - Code execution
• window, document, globalThis - Global objects
• constructor, __proto__ - Prototype chain
• fetch, XMLHttpRequest - Network requests (use fetch action)