1 files changed, 49 insertions, 0 deletions
diff --git a/school/node_modules/graphql/validation/rules/NoUnusedVariablesRule.js.flow b/school/node_modules/graphql/validation/rules/NoUnusedVariablesRule.js.flow
new file mode 100644
index 0000000..ed284c8
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+++ b/school/node_modules/graphql/validation/rules/NoUnusedVariablesRule.js.flow
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+// @flow strict
+import { GraphQLError } from '../../error/GraphQLError';
+
+import type { ASTVisitor } from '../../language/visitor';
+
+import type { ValidationContext } from '../ValidationContext';
+
+/**
+ * No unused variables
+ *
+ * A GraphQL operation is only valid if all variables defined by an operation
+ * are used, either directly or within a spread fragment.
+ */
+export function NoUnusedVariablesRule(context: ValidationContext): ASTVisitor {
+  let variableDefs = [];
+
+  return {
+    OperationDefinition: {
+      enter() {
+        variableDefs = [];
+      },
+      leave(operation) {
+        const variableNameUsed = Object.create(null);
+        const usages = context.getRecursiveVariableUsages(operation);
+
+        for (const { node } of usages) {
+          variableNameUsed[node.name.value] = true;
+        }
+
+        for (const variableDef of variableDefs) {
+          const variableName = variableDef.variable.name.value;
+          if (variableNameUsed[variableName] !== true) {
+            context.reportError(
+              new GraphQLError(
+                operation.name
+                  ? `Variable "$${variableName}" is never used in operation "${operation.name.value}".`
+                  : `Variable "$${variableName}" is never used.`,
+                variableDef,
+              ),
+            );
+          }
+        }
+      },
+    },
+    VariableDefinition(def) {
+      variableDefs.push(def);
+    },
+  };
+}