fix(graphql-language-service): fix off by one on hover

.changeset/dry-queens-return.md

@@ -0,0 +1,5 @@
+---
+'graphql-language-service': patch
+---
+
+Fix off-by-one when hovering over token

packages/graphql-language-service/src/interface/__tests__/getHoverInformation.test.ts

@@ -30,14 +30,35 @@ describe('getHoverInformation', () => {
     return getHoverInformation(schema, query, point);
   }
 
-  it('provides leaf field information', () => {
-    const actual = testHover(
-      'query { thing { testField } }',
-      new Position(0, 20),
-    );
-    expect(actual).toEqual(
-      'TestType.testField: String\n\nThis is field documentation for TestType.testField',
-    );
+  describe('provides leaf field information', () => {
+    it('when in middle of token', () => {
+      const actual = testHover(
+        'query { thing { testField } }',
+        new Position(0, 20),
+      );
+      expect(actual).toEqual(
+        'TestType.testField: String\n\nThis is field documentation for TestType.testField',
+      );
+    });
+
+    it('when at start of token', () => {
+      const actual = testHover(
+        'query { thing { testField } }',
+        new Position(0, 16),
+      );
+      expect(actual).toEqual(
+        'TestType.testField: String\n\nThis is field documentation for TestType.testField',
+      );
+    });
+    it('when at end of token', () => {
+      const actual = testHover(
+        'query { thing { testField } }',
+        new Position(0, 24),
+      );
+      expect(actual).toEqual(
+        'TestType.testField: String\n\nThis is field documentation for TestType.testField',
+      );
+    });
   });
 
   it('provides aliased field information', () => {

packages/graphql-language-service/src/interface/getAutocompleteSuggestions.ts

@@ -148,6 +148,7 @@ export function getAutocompleteSuggestions(
     schema,
     contextToken,
     options,
+    1,
   );
   if (!context) {
     return [];

packages/graphql-language-service/src/parser/api.ts

@@ -176,14 +176,15 @@ export function getContextAtPosition(
   schema: GraphQLSchema,
   contextToken?: ContextToken,
   options?: { mode?: GraphQLDocumentMode; uri?: string },
+  offset = 0,
 ): {
   token: ContextToken;
   state: State;
   typeInfo: ReturnType<typeof getTypeInfo>;
   mode: GraphQLDocumentMode;
 } | null {
   const token: ContextToken =
-    contextToken || getTokenAtPosition(queryText, cursor, 1);
+    contextToken || getTokenAtPosition(queryText, cursor, offset);
   if (!token) {
     return null;
   }