fix: enable prettier formatter for umd (#2)

demo/index.html

@@ -30,6 +30,7 @@
         'vs/basic-languages': '../node_modules/monaco-languages/release/dev',
         'vs/language/yaml': '../lib/dev',
         vs: '../node_modules/monaco-editor-core/dev/vs',
+        prettier: '../node_modules/prettier',
       };
       if (document.location.protocol === 'http:') {
         // Add support for running local http server
@@ -51,6 +52,8 @@
       require([
         'vs/basic-languages/monaco.contribution',
         'vs/language/yaml/monaco.contribution',
+        'prettier/standalone',
+        'prettier/parser-yaml',
       ], function() {
         const yaml = `p1: `;
         const modelUri = monaco.Uri.parse('a://b/foo.json');
@@ -68,6 +71,7 @@
           hover: true,
           completion: true,
           validate: true,
+          format: true,
           schemas: [
             {
               uri: 'http://myserver/foo-schema.json', // id of the first schema

src/languageservice/services/yamlFormatter.ts

@@ -35,11 +35,12 @@ export class YAMLFormatter {
 
     try {
       const prettier = require('prettier/standalone');
+      const parser = require('prettier/parser-yaml');
       const text = document.getText();
 
       const formatted = prettier.format(
         text,
-        Object.assign(options, { parser: 'yaml' })
+        Object.assign(options, { parser: 'yaml', plugins: [parser] })
       );
 
       return [

src/monaco.d.ts

@@ -40,6 +40,8 @@ declare namespace monaco.languages.yaml {
      * Whether or not kubernetes yaml is supported
      */
     readonly isKubernetes?: boolean;
+
+    readonly format?: boolean;
   }
 
   export interface LanguageServiceDefaults {