WIP: projectPreprocessor-perf

Author: matz3

lib/projectPreprocessor.js

@@ -231,7 +231,12 @@ class ProjectPreprocessor {
 			return config.kind === "extension";
 		});
 
-		const projectClone = JSON.parse(JSON.stringify(project));
+		let projectStringified;
+		if (extensionConfigs.length) {
+			// Stringify the project before making modifications
+			// Using a string to efficiently create multiple independent clones
+			projectStringified = JSON.stringify(project);
+		}
 
 		// While a project can contain multiple configurations,
 		//	from a dependency tree perspective it is always a single project
@@ -255,7 +260,7 @@ class ProjectPreprocessor {
 
 		const extensionProjects = extensionConfigs.map((config) => {
 			// Clone original project
-			const configuredProject = JSON.parse(JSON.stringify(projectClone));
+			const configuredProject = JSON.parse(projectStringified);
 
 			// Enhance project with its configuration
 			Object.assign(configuredProject, config);