fix shared styles

Author: mathieudutour

src/jsonUtils/nodeImpl/sharedTextStyles.ts

@@ -3,7 +3,7 @@ import { SketchDocument, TextStyle } from '../../types';
 import { generateID } from '../models';
 
 class TextStyles {
-  setDocument(_doc: SketchDocument) {
+  setDocument(_doc?: SketchDocument) {
     return this;
   }
 

src/jsonUtils/sketchImpl/sharedTextStyles.ts

@@ -13,7 +13,7 @@ class TextStyles {
     this._document = null;
   }
 
-  setDocument(doc: SketchDocument) {
+  setDocument(doc?: SketchDocument) {
     invariant(doc, 'Please provide a sketch document reference');
 
     this._document = doc;

src/sharedStyles/TextStyles.ts

@@ -51,10 +51,6 @@ const create = (styles: { [key: string]: TextStyle }, options: Options = {}): St
 
   const doc = getDocument(document);
 
-  if (!doc) {
-    return {};
-  }
-
   if (sketchVersion !== 'NodeJS' && sketchVersion < 50) {
     doc.showMessage('💎 Requires Sketch 50+ 💎');
     return {};