move formatError to graphqlerror and re-export

Follow-up #4324

src/error/GraphQLError.js

@@ -1,3 +1,4 @@
+import devAssert from '../jsutils/devAssert';
 import isObjectLike from '../jsutils/isObjectLike';
 import { SYMBOL_TO_STRING_TAG } from '../polyfills/symbols';
 
@@ -7,9 +8,6 @@ import type { SourceLocation } from '../language/location';
 import { getLocation } from '../language/location';
 import { printLocation, printSourceLocation } from '../language/printLocation';
 
-import { formatError } from './formatError';
-import type { GraphQLFormattedError } from './formatError';
-
 /**
  * A GraphQLError describes an Error found during the parse, validate, or
  * execute phases of performing a GraphQL operation. In addition to a message
@@ -198,3 +196,48 @@ export function printError(error: GraphQLError): string {
 
   return output;
 }
+
+/**
+ * Given a GraphQLError, format it according to the rules described by the
+ * Response Format, Errors section of the GraphQL Specification.
+ */
+export function formatError(error: GraphQLError): GraphQLFormattedError {
+  devAssert(error, 'Received null or undefined error.');
+  const message = error.message ?? 'An unknown error occurred.';
+  const locations = error.locations;
+  const path = error.path;
+  const extensions = error.extensions;
+
+  return extensions && Object.keys(extensions).length > 0
+    ? { message, locations, path, extensions }
+    : { message, locations, path };
+}
+
+/**
+ * @see https://github.com/graphql/graphql-spec/blob/master/spec/Section%207%20--%20Response.md#errors
+ */
+export type GraphQLFormattedError = {|
+  /**
+   * A short, human-readable summary of the problem that **SHOULD NOT** change
+   * from occurrence to occurrence of the problem, except for purposes of
+   * localization.
+   */
+  +message: string,
+  /**
+   * If an error can be associated to a particular point in the requested
+   * GraphQL document, it should contain a list of locations.
+   */
+  +locations: $ReadOnlyArray<SourceLocation> | void,
+  /**
+   * If an error can be associated to a particular field in the GraphQL result,
+   * it _must_ contain an entry with the key `path` that details the path of
+   * the response field which experienced the error. This allows clients to
+   * identify whether a null result is intentional or caused by a runtime error.
+   */
+  +path: $ReadOnlyArray<string | number> | void,
+  /**
+   * Reserved for implementors to extend the protocol however they see fit,
+   * and hence there are no additional restrictions on its contents.
+   */
+  +extensions?: { [key: string]: mixed, ... },
+|};

src/error/formatError.js

@@ -1,50 +1 @@
-import devAssert from '../jsutils/devAssert';
-
-import type { SourceLocation } from '../language/location';
-
-import type { GraphQLError } from './GraphQLError';
-
-/**
- * Given a GraphQLError, format it according to the rules described by the
- * Response Format, Errors section of the GraphQL Specification.
- */
-export function formatError(error: GraphQLError): GraphQLFormattedError {
-  devAssert(error, 'Received null or undefined error.');
-  const message = error.message ?? 'An unknown error occurred.';
-  const locations = error.locations;
-  const path = error.path;
-  const extensions = error.extensions;
-
-  return extensions && Object.keys(extensions).length > 0
-    ? { message, locations, path, extensions }
-    : { message, locations, path };
-}
-
-/**
- * @see https://github.com/graphql/graphql-spec/blob/master/spec/Section%207%20--%20Response.md#errors
- */
-export type GraphQLFormattedError = {|
-  /**
-   * A short, human-readable summary of the problem that **SHOULD NOT** change
-   * from occurrence to occurrence of the problem, except for purposes of
-   * localization.
-   */
-  +message: string,
-  /**
-   * If an error can be associated to a particular point in the requested
-   * GraphQL document, it should contain a list of locations.
-   */
-  +locations: $ReadOnlyArray<SourceLocation> | void,
-  /**
-   * If an error can be associated to a particular field in the GraphQL result,
-   * it _must_ contain an entry with the key `path` that details the path of
-   * the response field which experienced the error. This allows clients to
-   * identify whether a null result is intentional or caused by a runtime error.
-   */
-  +path: $ReadOnlyArray<string | number> | void,
-  /**
-   * Reserved for implementors to extend the protocol however they see fit,
-   * and hence there are no additional restrictions on its contents.
-   */
-  +extensions?: { [key: string]: mixed, ... },
-|};
+export { formatError, GraphQLFormattedError } from './GraphQLError';