无法从 apollo-server-express 导入 SchemaDirectiveVisitor

Question

const { SchemaDirectiveVisitor } = require('apollo-server-express');

class ReplaceDirective extends SchemaDirectiveVisitor {
visitFieldDefinition(field) {
    const { replacement } = this.args;
    field.resolve = () => {
        return replacement
    }
}
}

module.exports = Object.freeze({ ReplaceDirective })

The Error I am getting is following TypeError: Class extends value undefined is not a constructor or null

Answer 1

Looking at the apollo-server\/packages\/apollo-server-express\/src\/index.ts<\/a> , that function is not exposed.

Answer 2

They got rid of the SchemaDirectiveVisitor and added two new functions to simplify: mapSchema and getDirectives.

Source: https://www.the-guild.dev/blog/graphql-tools-v6 Then scroll to the following title. Modify Schemas with Directives