import { has_key } from "https://deno.land/x/denops_std@v4.1.3/function/mod.ts";
The result is a Number, which is TRUE if |Dictionary| {dict} has an entry with key {key}. FALSE otherwise. The {key} argument is a string. In |Vim9| script a number is also accepted (and converted to a string) but no other types. In legacy script the usual automatic conversion to string is done. Can also be used as a |method|: mydict->has_key(key)