Add plugin support

README.md

@@ -51,6 +51,10 @@ You can turn on format-on-save on a per-language basis by scoping the setting:
 
 `eslint`, `tslint`, and all peer dependencies required by your specific configuration must be installed locally.  Global installations will not be recognized.
 
+### Prettier Plugins
+
+Prettier plugins are supported when using a local Prettier installation. Just install the plugin you need locally to your project, restart vscode and you are good to go.
+
 ## Settings
 
 ### Prettier's Settings

src/PrettierEditProvider.ts

@@ -6,10 +6,11 @@ import {
     FormattingOptions,
     CancellationToken,
     TextEdit,
+    window,
 } from 'vscode';
 
 import { safeExecution, addToOutput, setUsedModule } from './errorHandler';
-import { getParsersFromLanguageId, getConfig } from './utils';
+import { getParsersFromLanguageId, getConfig, supportsLanguage } from './utils';
 import { requireLocalPkg } from './requirePkg';
 
 import {
@@ -103,6 +104,13 @@ async function format(
         return text;
     }
 
+    if (!supportsLanguage(languageId, localPrettier)) {
+        window.showErrorMessage(
+            `Prettier does not support "${languageId}". Maybe a plugin is missing from the workspace?`
+        );
+        return text;
+    }
+
     const dynamicParsers = getParsersFromLanguageId(
         languageId,
         localPrettier,

src/utils.ts

@@ -6,6 +6,7 @@ import {
     PrettierSupportInfo,
     ParserOption,
 } from './types.d';
+import { requireLocalPkg } from './requirePkg';
 
 const bundledPrettier = require('prettier') as Prettier;
 
@@ -35,8 +36,35 @@ export function getParsersFromLanguageId(
 }
 
 export function allEnabledLanguages(): string[] {
-    return getSupportLanguages().reduce(
-        (ids, language) => [...ids, ...(language.vscodeLanguageIds || [])],
+    if (!workspace.workspaceFolders) {
+        return getSupportLanguages().reduce(
+            (ids, language) => [...ids, ...(language.vscodeLanguageIds || [])],
+            [] as string[]
+        );
+    }
+
+    return workspace.workspaceFolders.reduce(
+        (ids, workspaceFolder) => {
+            const workspacePrettier = requireLocalPkg(
+                workspaceFolder.uri.fsPath,
+                'prettier'
+            ) as Prettier;
+
+            const newLanguages: string[] = [];
+
+            for (const language of getSupportLanguages(workspacePrettier)) {
+                if (!language.vscodeLanguageIds) {
+                    continue;
+                }
+                for (const id of language.vscodeLanguageIds) {
+                    if (!ids.includes(id)) {
+                        newLanguages.push(id);
+                    }
+                }
+            }
+
+            return [...ids, ...newLanguages];
+        },
         [] as string[]
     );
 }
@@ -59,3 +87,18 @@ export function getGroup(group: string): PrettierSupportInfo['languages'] {
 function getSupportLanguages(prettierInstance: Prettier = bundledPrettier) {
     return prettierInstance.getSupportInfo(prettierInstance.version).languages;
 }
+
+export function supportsLanguage(
+    vscodeLanguageId: string,
+    prettierInstance: Prettier
+) {
+    return prettierInstance
+        .getSupportInfo(prettierInstance.version)
+        .languages.some(language => {
+            if (!language.vscodeLanguageIds) {
+                return false;
+            }
+
+            return language.vscodeLanguageIds.includes(vscodeLanguageId);
+        });
+}