Initialisation

Added the packages and files for the backend server

node_modules/graphql/validation/rules/UniqueDirectiveNamesRule.mjs

@@ -0,0 +1,47 @@
+import { GraphQLError } from '../../error/GraphQLError.mjs';
+
+/**
+ * Unique directive names
+ *
+ * A GraphQL document is only valid if all defined directives have unique names.
+ */
+export function UniqueDirectiveNamesRule(context) {
+  const knownDirectiveNames = Object.create(null);
+  const schema = context.getSchema();
+  return {
+    DirectiveDefinition(node) {
+      const directiveName = node.name.value;
+
+      if (
+        schema !== null &&
+        schema !== void 0 &&
+        schema.getDirective(directiveName)
+      ) {
+        context.reportError(
+          new GraphQLError(
+            `Directive "@${directiveName}" already exists in the schema. It cannot be redefined.`,
+            {
+              nodes: node.name,
+            },
+          ),
+        );
+        return;
+      }
+
+      if (knownDirectiveNames[directiveName]) {
+        context.reportError(
+          new GraphQLError(
+            `There can be only one directive named "@${directiveName}".`,
+            {
+              nodes: [knownDirectiveNames[directiveName], node.name],
+            },
+          ),
+        );
+      } else {
+        knownDirectiveNames[directiveName] = node.name;
+      }
+
+      return false;
+    },
+  };
+}