feat(dev-infra): create the prettier formatter for ng-dev format tooling (#41824)

Add support to use prettier for formatting using `ng-dev format`.

PR Close #41824

dev-infra/format/formatters/base-formatter.ts

@@ -46,7 +46,7 @@ export abstract class Formatter {
   /** The default matchers for the formatter for filtering files to be formatted. */
   abstract defaultFileMatcher: string[];
 
-  constructor(private config: FormatConfig) {}
+  constructor(protected config: FormatConfig) {}
 
   /**
    * Retrieve the command to execute the provided action, including both the binary

dev-infra/format/formatters/index.ts

@@ -10,14 +10,18 @@ import {getFormatConfig} from '../config';
 
 import {Buildifier} from './buildifier';
 import {ClangFormat} from './clang-format';
+import {Prettier} from './prettier';
 
 /**
  * Get all defined formatters which are active based on the current loaded config.
  */
 export function getActiveFormatters() {
   const config = getFormatConfig().format;
-  return [new Buildifier(config), new ClangFormat(config)].filter(
-      formatter => formatter.isEnabled());
+  return [
+    new Prettier(config),
+    new Buildifier(config),
+    new ClangFormat(config),
+  ].filter((formatter) => formatter.isEnabled());
 }
 
 // Rexport symbols used for types elsewhere.

dev-infra/format/formatters/prettier.ts

@@ -0,0 +1,55 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {join} from 'path';
+import {exec} from 'shelljs';
+
+import {error} from '../../utils/console';
+
+import {Formatter} from './base-formatter';
+
+/**
+ * Formatter for running prettier against Typescript and Javascript files.
+ */
+export class Prettier extends Formatter {
+  name = 'prettier';
+
+  binaryFilePath = join(this.git.baseDir, 'node_modules/.bin/prettier');
+
+  defaultFileMatcher = ['**/*.{t,j}s'];
+
+  /**
+   * The configuration path of the pretter config, obtained during construction to prevent needing
+   * to discover it repeatedly for each execution.
+   */
+  private configPath =
+      this.config['pretter'] ? exec(`${this.binaryFilePath} --find-config-path .`).trim() : '';
+
+  actions = {
+    check: {
+      commandFlags: `--config ${this.configPath} --check`,
+      callback:
+          (_: string, code: number, stdout: string) => {
+            return code !== 0;
+          },
+    },
+    format: {
+      commandFlags: `--config ${this.configPath} --write`,
+      callback:
+          (file: string, code: number, _: string, stderr: string) => {
+            if (code !== 0) {
+              error(`Error running prettier on: ${file}`);
+              error(stderr);
+              error();
+              return true;
+            }
+            return false;
+          },
+    },
+  };
+}

dev-infra/ng-dev.js

@@ -2463,6 +2463,50 @@ class ClangFormat extends Formatter {
     }
 }
 
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+/**
+ * Formatter for running prettier against Typescript and Javascript files.
+ */
+class Prettier extends Formatter {
+    constructor() {
+        super(...arguments);
+        this.name = 'prettier';
+        this.binaryFilePath = path.join(this.git.baseDir, 'node_modules/.bin/prettier');
+        this.defaultFileMatcher = ['**/*.{t,j}s'];
+        /**
+         * The configuration path of the pretter config, obtained during construction to prevent needing
+         * to discover it repeatedly for each execution.
+         */
+        this.configPath = this.config['pretter'] ? shelljs.exec(`${this.binaryFilePath} --find-config-path .`).trim() : '';
+        this.actions = {
+            check: {
+                commandFlags: `--config ${this.configPath} --check`,
+                callback: (_, code, stdout) => {
+                    return code !== 0;
+                },
+            },
+            format: {
+                commandFlags: `--config ${this.configPath} --write`,
+                callback: (file, code, _, stderr) => {
+                    if (code !== 0) {
+                        error(`Error running prettier on: ${file}`);
+                        error(stderr);
+                        error();
+                        return true;
+                    }
+                    return false;
+                },
+            },
+        };
+    }
+}
+
 /**
  * @license
  * Copyright Google LLC All Rights Reserved.
@@ -2475,7 +2519,11 @@ class ClangFormat extends Formatter {
  */
 function getActiveFormatters() {
     const config = getFormatConfig().format;
-    return [new Buildifier(config), new ClangFormat(config)].filter(formatter => formatter.isEnabled());
+    return [
+        new Prettier(config),
+        new Buildifier(config),
+        new ClangFormat(config),
+    ].filter((formatter) => formatter.isEnabled());
 }
 
 /**

dev-infra/tmpl-package.json

@@ -46,6 +46,9 @@
     "clang-format": {
       "optional": true
     },
+    "prettier": {
+      "optional": true
+    },
     "protractor": {
       "optional": true
     },