rontolisp:promisep

(rontolisp:promisep value)

Returns t if value is a promise — as returned by rontolisp:fetch or rontolisp:then — and nil otherwise.

A promise is an opaque value: it has no reader syntax and prints as #<PROMISE>.

Backend support

Works on every backend and in every WASM mode (Preview 1 included), like rontolisp:await and rontolisp:then.