diff --git a/src/core/documents.ts b/src/core/documents.ts
index 92ff773b4f3..1b1d6721a9d 100644
--- a/src/core/documents.ts
+++ b/src/core/documents.ts
@@ -186,7 +186,7 @@ export default class Documents implements Disposable {
     return docs
   }
 
-  public getDocument(uri: number | string, caseInsensitive = platform.isWindows || platform.isMacintosh): Document | null {
+  public getDocument(uri: number | string, caseInsensitive = platform.isWindows || platform.isMacintosh): Document | null | undefined {
     if (typeof uri === 'number') {
       return this.buffers.get(uri)
     }
diff --git a/src/workspace.ts b/src/workspace.ts
index 0d697f5efac..61d9adf60d6 100644
--- a/src/workspace.ts
+++ b/src/workspace.ts
@@ -357,13 +357,13 @@ export class Workspace {
   /**
    * Get created document by uri or bufnr.
    */
-  public getDocument(uri: number | string): Document | null {
+  public getDocument(uri: number | string): Document | null | undefined {
     return this.documentsManager.getDocument(uri)
   }
 
   public hasDocument(uri: string, version?: number): boolean {
     let doc = this.documentsManager.getDocument(uri)
-    return doc != null && (version != null ? doc.version == version : true)
+    return doc && (version != null ? doc.version == version : true)
   }
 
   public getUri(bufnr: number, defaultValue = ''): string {
diff --git a/typings/index.d.ts b/typings/index.d.ts
index 81a37bc8adf..143011e2353 100644
--- a/typings/index.d.ts
+++ b/typings/index.d.ts
@@ -8934,7 +8934,7 @@ declare module 'coc.nvim' {
     /**
      * Get created document by uri or bufnr.
      */
-    export function getDocument(uri: number | string): Document
+    export function getDocument(uri: number | string): Document | null | undefined
 
     /**
      * Apply WorkspaceEdit.