TemplateValuestype

PossibleString | ImmutableArray<unknown> | ImmutableDictionary<unknown> | ((placeholder: string) => string)

Type
`PossibleString`	Things that can be reliably converted to a string with no confusion.
`ImmutableArray`	Immutable array: an array that cannot be changed.
`ImmutableDictionary`	Readonly dictionary object.

Things that can be converted to the value for a named placeholder.

PossibleString — Single string used for every {placeholder}
ImmutableArray<string> — Array of strings (or functions that return strings) used for * numbered placeholders e.g. ["John"]
ImmutableDictionary<PossibleString> — Object containing named strings used for named placeholders, e.g. { val1: "Ellie", val2: 123 }
(placeholder: string) => string — Function that returns the right string for a named {placeholder}.