derw/src/builtins.ts

An Elm-inspired language that transpiles to TypeScript

type BuiltinTypes =
    | "boolean"
    | "number"
    | "string"
    | "void"
    | "any"
    | "Promise";

export function isBuiltinType(
    potentialType: string
): potentialType is BuiltinTypes {
    return (
        [ "boolean", "number", "string", "void", "any", "Promise" ].indexOf(
            potentialType
        ) > -1
    );
}

export function isReservedName(potentialName: string): boolean {
    return [ "Object", "Function" ].indexOf(potentialName.trim()) > -1;
}