Variables varExists

$varExists[]

$varExists is used to safely check whether a temporary variable has been set before attempting to read it. Since $var returns an empty string for missing variables (silent failure), $varExists is the only reliable way to distinguish between “variable exists with an empty value” and “variable does not exist.”

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Syntax

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$varExists[name]

Return Value

The return value is always the string "true" or "false" — not a boolean. Use string comparison in conditionals:

$if[$varExists[name]==true]
$if[$varExists[name]!=false]

Both forms work. $if[$varExists[name]] alone will always be truthy (non-empty string), so always compare explicitly.

Scope

This function only checks temporary variables created with $var. It does not check global or user-scoped variables — those would need to be checked by attempting $getVar and comparing the result.

Use Cases

Lazy initialization: set a variable only if it hasn’t been set yet.
Guard clauses: skip logic that depends on a variable being present.
Debugging: verify that expected intermediate values are available.

Examples

Checking Variable Configuration

$if[$varExists[userScore]==true]
  $title[Score System Online]
  $description[Your score: **$getUserVar[userScore]**]
  $color[#57F287]
$else
  $title[System Offline]
  $description[The `userScore` variable is not configured.]
  $color[#ED4245]
$endif
$sendMessage[]