@graphql-codegen/visitor-plugin-common/esm/graphql-type-utils.js

import { isIntrospectionType, isSpecifiedScalarType } from 'graphql';
export const isNativeNamedType = (namedType) => {
    // "Native" NamedType in this context means the following:
    // 1. introspection types i.e. with `__` prefixes
    // 2. base scalars e.g. Boolean, Int, etc.
    // 3. Other natives (mostly base scalars) which was not defined in the schema i.e. no `astNode`
    if (isSpecifiedScalarType(namedType) || isIntrospectionType(namedType) || !namedType.astNode) {
        return true;
    }
    return false;
};