Appease TypeScript

Author: benjie

src/language/ast.ts

@@ -772,6 +772,6 @@ export interface SchemaCoordinateNode {
   readonly loc?: Location;
   readonly ofDirective: boolean;
   readonly name: NameNode;
-  readonly memberName?: NameNode;
-  readonly argumentName?: NameNode;
+  readonly memberName?: NameNode | undefined;
+  readonly argumentName?: NameNode | undefined;
 }

src/language/parser.ts

@@ -1468,11 +1468,11 @@ export class Parser {
     const start = this._lexer.token;
     const ofDirective = this.expectOptionalToken(TokenKind.AT);
     const name = this.parseName();
-    let memberName;
+    let memberName: NameNode | undefined;
     if (!ofDirective && this.expectOptionalToken(TokenKind.DOT)) {
       memberName = this.parseName();
     }
-    let argumentName;
+    let argumentName: NameNode | undefined;
     if (
       (ofDirective || memberName) &&
       this.expectOptionalToken(TokenKind.PAREN_L)

src/language/printer.ts

@@ -326,7 +326,7 @@ const printDocASTReducer: ASTReducer<string> = {
   SchemaCoordinate: {
     leave: ({ ofDirective, name, memberName, argumentName }) =>
       join([
-        ofDirective && '@',
+        ofDirective ? '@' : '',
         name,
         wrap('.', memberName),
         wrap('(', argumentName, ':)'),