Add error msg when extensionsPath is not found

package.json

@@ -1,6 +1,6 @@
 {
   "name": "vscode-emmet-helper",
-  "version": "1.0.19",
+  "version": "1.0.20",
   "description": "Helper to use emmet modules in Visual Studio Code",
   "main": "./out/emmetHelper.js",
   "types": "./out/emmetHelper.d.ts",
@@ -24,7 +24,7 @@
     "vscode-languageserver-types": "^3.0.3"
   },
   "scripts": {
-    "prepublish": "npm run compile",
+    "prepublish": "npm run compile && npm run test",
     "compile": "tsc -p ./ && cpy ./src/expand/*.js ./out/expand",
     "test": "mocha out/test"
   }

src/emmetHelper.ts

@@ -444,13 +444,18 @@ function getVariables(variablesFromSettings: object): any {
  * Updates customizations from snippets.json and syntaxProfiles.json files in the directory configured in emmet.extensionsPath setting
  */
 export function updateExtensionsPath(emmetExtensionsPath: string): Promise<void> {
-	if (!emmetExtensionsPath || !emmetExtensionsPath.trim() || !path.isAbsolute(emmetExtensionsPath.trim()) || !dirExists(emmetExtensionsPath.trim())) {
-		customSnippetRegistry = {};
-		snippetKeyCache.clear();
-		profilesFromFile = {};
-		variablesFromFile = {};
+	if (!emmetExtensionsPath || !emmetExtensionsPath.trim()) {
+		resetSettingsFromFile();
 		return Promise.resolve();
 	}
+	if (!path.isAbsolute(emmetExtensionsPath.trim())) {
+		resetSettingsFromFile();
+		return Promise.reject('The path provided in emmet.extensionsPath setting should be absoulte path');
+	}
+	if (!dirExists(emmetExtensionsPath.trim())) {
+		resetSettingsFromFile();
+		return Promise.reject(`The directory ${emmetExtensionsPath.trim()} doesnt exist. Update emmet.extensionsPath setting`);
+	}
 
 	let dirPath = emmetExtensionsPath.trim();
 	let snippetsPath = path.join(dirPath, 'snippets.json');
@@ -516,6 +521,13 @@ function dirExists(dirPath: string): boolean {
 	}
 }
 
+function resetSettingsFromFile(){
+	customSnippetRegistry = {};
+	snippetKeyCache.clear();
+	profilesFromFile = {};
+	variablesFromFile = {};
+}
+
 /**
 * Get the corresponding emmet mode for given vscode language mode
 * Eg: jsx for typescriptreact/javascriptreact or pug for jade