json.validate Synchronous

Check whether text is syntactically valid JSON without keeping a decoded value. Use this to accept or reject edited text before storing it.

Syntax

Luau

json.validate(
    text: string,
    options: JsonDecodeOptions?
) -> (true) OR (false, message: string, position: number)

Parameters

Function parameters
Parameter	Type	Description
`text`	`string`	JSON document to check.
`options`	`JsonDecodeOptions?`	Optional useNull boolean or options table. By default null becomes json.null and maxDepth is 256.

JsonDecodeOptions fields

Luau

JsonDecodeOptions = boolean | {useNull: boolean?, maxDepth: number?}

Field	Description
`useNull`	Defaults to true, preserving JSON null as json.null. false converts null to nil, which can remove table entries. A boolean options argument is shorthand for this field.
`maxDepth`	Maximum nesting depth. Defaults to 256; an integer is required and is clamped to 1–4096.

(true) OR (false, message: string, position: number)

true for valid JSON; otherwise false, an error message, and its position.

Validation does not check application-specific field names or types. Bad argument types still raise an error.

Luau

local ok, message, position = json.validate('{"enabled":true}')
if not ok then print(message, position) end
print(ok) -- true