diff --git a/packages/domutils/src/clipboard.ts b/packages/domutils/src/clipboard.ts
index 15e6ac0ec..2dbec5784 100644
--- a/packages/domutils/src/clipboard.ts
+++ b/packages/domutils/src/clipboard.ts
@@ -18,6 +18,7 @@ export namespace ClipboardExt {
    * @param text - The text to copy to the clipboard.
    */
   export function copyText(text: string): void {
+    if (typeof document === 'undefined') return;
     // Fetch the document body.
     const body = document.body;
 
diff --git a/packages/domutils/src/platform.ts b/packages/domutils/src/platform.ts
index 1cf53c7e3..334be6263 100644
--- a/packages/domutils/src/platform.ts
+++ b/packages/domutils/src/platform.ts
@@ -15,22 +15,26 @@ export namespace Platform {
   /**
    * A flag indicating whether the platform is Mac.
    */
-  export const IS_MAC = !!navigator.platform.match(/Mac/i);
+  export const IS_MAC =
+    typeof navigator !== 'undefined' && !!navigator.platform.match(/Mac/i);
 
   /**
    * A flag indicating whether the platform is Windows.
    */
-  export const IS_WIN = !!navigator.platform.match(/Win/i);
+  export const IS_WIN =
+    typeof navigator !== 'undefined' && !!navigator.platform.match(/Win/i);
 
   /**
    * A flag indicating whether the browser is IE.
    */
-  export const IS_IE = /Trident/.test(navigator.userAgent);
+  export const IS_IE =
+    typeof navigator !== 'undefined' && /Trident/.test(navigator.userAgent);
 
   /**
    * A flag indicating whether the browser is Edge.
    */
-  export const IS_EDGE = /Edge/.test(navigator.userAgent);
+  export const IS_EDGE =
+    typeof navigator !== 'undefined' && /Edge/.test(navigator.userAgent);
 
   /**
    * Test whether the `accel` key is pressed.
diff --git a/packages/domutils/src/selector.ts b/packages/domutils/src/selector.ts
index 68bd9210c..ddc4f62b5 100644
--- a/packages/domutils/src/selector.ts
+++ b/packages/domutils/src/selector.ts
@@ -109,13 +109,17 @@ namespace Private {
   /**
    * An empty element for testing selector validity.
    */
-  export const testElem = document.createElement('div');
+  export const testElem =
+    typeof document !== 'undefined'
+      ? document.createElement('div')
+      : ({} as any);
 
   /**
    * A cross-browser CSS selector matching prototype function.
    */
   export const protoMatchFunc = (() => {
-    let proto = Element.prototype as any;
+    let proto =
+      typeof Element === 'undefined' ? ({} as any) : Element.prototype;
     return (
       proto.matches ||
       proto.matchesSelector ||