diff --git a/changelog.md b/changelog.md
index e71c653c5..a503bcf52 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,6 +1,7 @@
 ### Unreleased
 
 - Moved typescript from dev-dependencies to dependencies as it's needed by the typescript-eslint-parser
+- Added support for typescript definition files
 - Cleaned up ignore files and publish contents
 
 ### 3.1.0
diff --git a/src/language-js/reprinter/index.ts b/src/language-js/reprinter/index.ts
index 0cb876c0d..4e3a7da9d 100644
--- a/src/language-js/reprinter/index.ts
+++ b/src/language-js/reprinter/index.ts
@@ -186,6 +186,7 @@ export class Reprinter implements ILanguage {
           case "DebuggerStatement":
           case "EmptyStatement":
           case "Literal":
+          case "OptionalMemberExpression":
           case "RestProperty":
           case "SpreadElement":
           case "Super":
@@ -323,7 +324,9 @@ export class Reprinter implements ILanguage {
             break;
           }
           case "FunctionExpression": {
-            nodes.push(node.body);
+            if (node.body != null) {
+              nodes.push(node.body);
+            }
             break;
           }
           case "Identifier":
@@ -517,6 +520,7 @@ export class Reprinter implements ILanguage {
           case "TSArrayType":
           case "TSAsExpression":
           case "TSBooleanKeyword":
+          case "TSConditionalType":
           case "TSConstructorType":
           case "TSEnumDeclaration":
           case "TSImportType":
diff --git a/src/language-js/reprinter/test_assets/typescript.generated_class_definition.input.ts.txt b/src/language-js/reprinter/test_assets/typescript.generated_class_definition.input.ts.txt
new file mode 100644
index 000000000..0fb62a96c
--- /dev/null
+++ b/src/language-js/reprinter/test_assets/typescript.generated_class_definition.input.ts.txt
@@ -0,0 +1,20 @@
+import { ReprinterOptions } from "../reprinter-options";
+export declare class Reprinter {
+    private static reprinters;
+    static rewriteFile(filename: string, options: ReprinterOptions): void;
+    static rewriteText(fileExtension: string, text: string, options: ReprinterOptions): string | undefined;
+    private static getReprinterForFile;
+}
+
+declare type ArgumentType<T> = T extends (...arg1: infer U) => any ? U : any;
+export declare enum LoggerVerboseOption {
+    Quiet = 0,
+    Normal = 1,
+    Diagnostic = 2
+}
+export declare class LogUtils {
+    private static verbosity;
+    static log(verbosity: LoggerVerboseOption, ...args: ArgumentType<typeof console.log>): void;
+    static setVerbosity(newVerbosity: LoggerVerboseOption): void;
+}
+export {};
diff --git a/src/language-js/reprinter/test_assets/typescript.generated_class_definition.output.ts.txt b/src/language-js/reprinter/test_assets/typescript.generated_class_definition.output.ts.txt
new file mode 100644
index 000000000..0fb62a96c
--- /dev/null
+++ b/src/language-js/reprinter/test_assets/typescript.generated_class_definition.output.ts.txt
@@ -0,0 +1,20 @@
+import { ReprinterOptions } from "../reprinter-options";
+export declare class Reprinter {
+    private static reprinters;
+    static rewriteFile(filename: string, options: ReprinterOptions): void;
+    static rewriteText(fileExtension: string, text: string, options: ReprinterOptions): string | undefined;
+    private static getReprinterForFile;
+}
+
+declare type ArgumentType<T> = T extends (...arg1: infer U) => any ? U : any;
+export declare enum LoggerVerboseOption {
+    Quiet = 0,
+    Normal = 1,
+    Diagnostic = 2
+}
+export declare class LogUtils {
+    private static verbosity;
+    static log(verbosity: LoggerVerboseOption, ...args: ArgumentType<typeof console.log>): void;
+    static setVerbosity(newVerbosity: LoggerVerboseOption): void;
+}
+export {};