getVar

Reads the current value of an App Var predefined at the app level in the LucyStudio designer.

Parameters

• appVarName (string): a variable name predefined in the LucyStudio app settings

Returns

any — the current value of the variable. Returns null if the variable name is not defined

Description

$app.getVar reads the value of a variable predefined at the app level in the LucyStudio designer. Internally it calls LucyVarMngr.getVarValue(appVarMap, appVarName).

The value is shared across the whole app, so you can read it with the same variable name from any Form or Page.

⚠️ The variable name must be predefined in the LucyStudio designer. An undefined variable name returns null.

$app vs $form vs $page comparison

Item	$app.getVar	$form.getVar
Scope	Shared across the app	Current Form instance
Where it's predefined	LucyStudio app settings	LucyStudio form settings
Lifecycle	Kept while the app runs	Destroyed when the Form closes
Access from another Form	✅ Yes	❌ No

Example

// Read an App Var
var userId = $app.getVar("loginUserId");
$log.i("로그인 사용자:", userId);

var theme = $app.getVar("theme");
if (theme === "dark") {
  // Handle dark mode
  $log.i("다크 모드 활성화");
}

// An undefined variable returns null
var unknown = $app.getVar("notDefined");
$log.i("미정의 변수:", unknown); // null

Related

• $app.setVar(appVarName, data) — set an App Var
• $app.clearVar(appVarName) — reset an App Var to its initial value
• $form.getVar(localVarName) — read a Form-level variable (valid only in that Form)
• $app.getSharedData(key) — read in-memory data under any key you like (no predefinition needed)