perf: avoid saving unchanged project data (#492)

src/electron/renderer.ts

@@ -278,9 +278,16 @@ Mobx.autorunAsync(() => {
 
 Mobx.autorunAsync(() => {
 	const project = store.getProject();
+	const savedProjects = store.getSavedProjects();
+	const savedProject = savedProjects[savedProjects.length - 1];
+
+	if (savedProject && Project.isEqual(savedProject, project.toDisk())) {
+		return;
+	}
 
 	if (project) {
 		const serializedProject = project.toJSON();
+		store.addSavedProject(project);
 
 		const payload = {
 			path: project.getPath(),

src/model/project.ts

@@ -1,4 +1,5 @@
 import { Element, ElementContent } from './element';
+import { isEqual } from 'lodash';
 import * as Mobx from 'mobx';
 import { Page } from './page';
 import { PatternLibrary } from './pattern-library';
@@ -120,6 +121,15 @@ export class Project {
 		return project;
 	}
 
+	public static isEqual(a: Types.SavedProject, b: Types.SavedProject): boolean;
+	public static isEqual(
+		a: Types.SavedProject | Project,
+		b: Types.SavedProject | Project
+	): boolean {
+		const toData = input => (input instanceof Project ? input.toDisk() : input);
+		return isEqual(toData(a), toData(b));
+	}
+
 	public addElement(element: Element): void {
 		this.elements.push(element);
 	}

src/store/view-store.ts

@@ -84,6 +84,8 @@ export class ViewStore {
 	 */
 	@Mobx.observable private redoBuffer: Command.Command[] = [];
 
+	private savedProjects: Types.SavedProject[] = [];
+
 	/**
 	 * http port the preview server is listening on
 	 */
@@ -148,6 +150,10 @@ export class ViewStore {
 		return page;
 	}
 
+	public addSavedProject(project: Model.Project): void {
+		this.savedProjects.push(project.toDisk());
+	}
+
 	/**
 	 * Clears the undo and redo buffers (e.g. if a page is loaded or the page state get
 	 * incompatible with the buffers).
@@ -513,6 +519,10 @@ export class ViewStore {
 		return this.project;
 	}
 
+	public getSavedProjects(): Types.SavedProject[] {
+		return this.savedProjects;
+	}
+
 	public getSelectedElement(): Model.Element | undefined {
 		if (!this.project) {
 			return;