method Node.isReadonlyableimport { Node } from "https://dotland.deno.dev/x/fresh@1.1.1/src/dev/deps.ts"; isReadonlyable<T extends Node>(node: T | undefined): node is ReadonlyableNode & ReadonlyableNodeExtensionType & TGets if the node is a ReadonlyableNode. Gets if the node is a ReadonlyableNode. Type ParametersT extends NodeParametersnode: T | undefined Node to check. Returnsnode is ReadonlyableNode & ReadonlyableNodeExtensionType & T