This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
The contents of a message are a sequence of pattern elements, which may be immediately defined literal values, a reference to a value that depends on another message, the value of some runtime variable, or some function defined elsewhere.
export type PatternElement = Expression | FunctionRef | Junk | Literal | Reserved | Text | VariableRef;
Depending on the syntax, pattern elements may be wrapped within an Expression.