Initialisation

Added the packages and files for the backend server

node_modules/graphql/validation/rules/UniqueFieldDefinitionNamesRule.mjs

@@ -0,0 +1,79 @@
+import { GraphQLError } from '../../error/GraphQLError.mjs';
+import {
+  isInputObjectType,
+  isInterfaceType,
+  isObjectType,
+} from '../../type/definition.mjs';
+
+/**
+ * Unique field definition names
+ *
+ * A GraphQL complex type is only valid if all its fields are uniquely named.
+ */
+export function UniqueFieldDefinitionNamesRule(context) {
+  const schema = context.getSchema();
+  const existingTypeMap = schema ? schema.getTypeMap() : Object.create(null);
+  const knownFieldNames = Object.create(null);
+  return {
+    InputObjectTypeDefinition: checkFieldUniqueness,
+    InputObjectTypeExtension: checkFieldUniqueness,
+    InterfaceTypeDefinition: checkFieldUniqueness,
+    InterfaceTypeExtension: checkFieldUniqueness,
+    ObjectTypeDefinition: checkFieldUniqueness,
+    ObjectTypeExtension: checkFieldUniqueness,
+  };
+
+  function checkFieldUniqueness(node) {
+    var _node$fields;
+
+    const typeName = node.name.value;
+
+    if (!knownFieldNames[typeName]) {
+      knownFieldNames[typeName] = Object.create(null);
+    } // FIXME: https://github.com/graphql/graphql-js/issues/2203
+
+    /* c8 ignore next */
+
+    const fieldNodes =
+      (_node$fields = node.fields) !== null && _node$fields !== void 0
+        ? _node$fields
+        : [];
+    const fieldNames = knownFieldNames[typeName];
+
+    for (const fieldDef of fieldNodes) {
+      const fieldName = fieldDef.name.value;
+
+      if (hasField(existingTypeMap[typeName], fieldName)) {
+        context.reportError(
+          new GraphQLError(
+            `Field "${typeName}.${fieldName}" already exists in the schema. It cannot also be defined in this type extension.`,
+            {
+              nodes: fieldDef.name,
+            },
+          ),
+        );
+      } else if (fieldNames[fieldName]) {
+        context.reportError(
+          new GraphQLError(
+            `Field "${typeName}.${fieldName}" can only be defined once.`,
+            {
+              nodes: [fieldNames[fieldName], fieldDef.name],
+            },
+          ),
+        );
+      } else {
+        fieldNames[fieldName] = fieldDef.name;
+      }
+    }
+
+    return false;
+  }
+}
+
+function hasField(type, fieldName) {
+  if (isObjectType(type) || isInterfaceType(type) || isInputObjectType(type)) {
+    return type.getFields()[fieldName] != null;
+  }
+
+  return false;
+}