feat(cli): add lb4 copyright command to generate/update file headers

docs/site/Copyright-generator.md

@@ -0,0 +1,85 @@
+---
+lang: en
+title: 'Generate copyright/license header for JavaScript/TypeScript files'
+keywords: LoopBack 4.0, LoopBack 4
+sidebar: lb4_sidebar
+permalink: /doc/en/lb4/Copyright-generator.html
+---
+
+### Synopsis
+
+The `lb4 copyright` command runs inside a Node.js project with `package.json` to
+add or update copyright/license header for JavaScript and TypeScript files based
+on `package.json` and git history.
+
+The command also supports [lerna](https://github.com/lerna/lerna) monorepos. It
+traverses all packages within the monorepo and apply copyright/license headers.
+
+```sh
+lb4 copyright [options]
+```
+
+The following is an example of such headers.
+
+```js
+// Copyright IBM Corp. 2020. All Rights Reserved.
+// Node module: @loopback/cli
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+```
+
+The year(s) is built from the git history of the file and `Node module` is read
+from the `name` property in `package.json`.
+
+Please note the command expects `git` is installed.
+
+### Options
+
+`--owner` : _(Optional)_ The owner of the copyright, such as `IBM Corp.`.
+
+`--license` : _(Optional)_ The name of the license, such as `MIT`.
+
+`--gitOnly` : _(Optional)_ A flag to control if only git tracked files are
+updated. Default to `true`.
+
+### Interactive Prompts
+
+The command prompts you for:
+
+1. The copyright owner. The default value is read from `copyright.owner` or
+   `author` in the `package.json`.
+
+2. The license name. The default value is read from `license` in the
+   `package.json`.
+
+The default owner is `IBM Corp.` and license is `MIT` with the following
+`package.json`.
+
+```json
+{
+  "name": "@loopback/boot",
+  "version": "2.0.2",
+  "author": "IBM Corp.",
+  "copyright.owner": "IBM Corp.",
+  "license": "MIT"
+}
+```
+
+### Output
+
+The following output is captured when `lb4 copyright` is run against
+[`loopback4-example-shopping`](https://github.com/strongloop/loopback4-example-shopping).
+
+```
+? Copyright owner: IBM Corp.
+? License name: (Use arrow keys or type to search)
+❯ MIT (MIT License)
+  ISC (ISC License)
+  Artistic-2.0 (Artistic License 2.0)
+  Apache-2.0 (Apache License 2.0)
+  ...
+? Do you want to update package.json and LICENSE? No
+Updating project loopback4-example-recommender (packages/recommender)
+Updating project loopback4-example-shopping (packages/shopping)
+Updating project loopback4-example-shopping-monorepo (.)
+```

docs/site/sidebars/lb4_sidebar.yml

@@ -559,6 +559,10 @@ children:
     url: Update-generator.html
     output: 'web, pdf'
 
+  - title: 'Generate copyright/license headers'
+    url: Copyright-generator.html
+    output: 'web, pdf'
+
 - title: 'Connectors reference'
   url: Connectors-reference.html
   output: 'web'

docs/site/tables/lb4-artifact-commands.html

@@ -76,12 +76,6 @@
       <td><a href="Interceptor-generator.html">Global interceptor generator</a></td>
     </tr>
 
-    <tr>
-      <td><code>lb4 update</code></td>
-      <td>Check and/or update project dependencies of LoopBack modules</td>
-      <td><a href="Update-generator.html">Project dependency update</a></td>
-    </tr>
-
     <tr>
       <td><code>lb4 rest-crud</code></td>
       <td>Generate rest configs for model endpoints</td>

docs/site/tables/lb4-project-commands.html

@@ -33,6 +33,18 @@
       </td>
     </tr>
 
+    <tr>
+      <td><code>lb4 update</code></td>
+      <td>Check and/or update project dependencies of LoopBack modules</td>
+      <td><a href="Update-generator.html">Project dependency update</a></td>
+    </tr>
+
+    <tr>
+      <td><code>lb4 copyright</code></td>
+      <td>Add or update copyright/license header for JavaScript/TypeScript files</td>
+      <td><a href="Copyright-generator.html">Copyright generator</a></td>
+    </tr>
+
     <tr>
       <td>
         <code>lb4 example</code>

packages/cli/generators/copyright/fs.js

@@ -0,0 +1,46 @@
+// Copyright IBM Corp. 2020. All Rights Reserved.
+// Node module: @loopback/cli
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+'use strict';
+
+const fse = require('fs-extra');
+const _ = require('lodash');
+const {promisify} = require('util');
+const glob = promisify(require('glob'));
+
+const defaultFS = {
+  write: fse.writeFile,
+  read: fse.readFile,
+  writeJSON: fse.writeJson,
+  readJSON: fse.readJson,
+  exists: fse.exists,
+};
+
+/**
+ * List all JS/TS files
+ * @param {string[]} paths - Paths to search
+ */
+async function jsOrTsFiles(cwd, paths = []) {
+  paths = [].concat(paths);
+  let globs;
+  if (paths.length === 0) {
+    globs = [glob('**/*.{js,ts}', {nodir: true, follow: false, cwd})];
+  } else {
+    globs = paths.map(p => {
+      if (/\/$/.test(p)) {
+        p += '**/*.{js,ts}';
+      } else if (!/[^*]\.(js|ts)$/.test(p)) {
+        p += '/**/*.{js,ts}';
+      }
+      return glob(p, {nodir: true, follow: false, cwd});
+    });
+  }
+  paths = await Promise.all(globs);
+  paths = _.flatten(paths);
+  return _.filter(paths, /\.(js|ts)$/);
+}
+
+exports.FSE = defaultFS;
+exports.jsOrTsFiles = jsOrTsFiles;

packages/cli/generators/copyright/git.js

@@ -0,0 +1,74 @@
+// Copyright IBM Corp. 2020. All Rights Reserved.
+// Node module: @loopback/cli
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+'use strict';
+
+const _ = require('lodash');
+const cp = require('child_process');
+const util = require('util');
+const debug = require('debug')('loopback:cli:copyright:git');
+
+const cache = new Map();
+
+/**
+ * Run a git command
+ * @param {string} cwd - Current directory to run the command
+ * @param  {...any} args - Args for the git command
+ */
+async function git(cwd, ...args) {
+  const cmd = 'git ' + util.format(...args);
+  const key = `${cwd}:${cmd}`;
+  debug('Running %s in directory', cmd, cwd);
+  if (cache.has(key)) {
+    return cache.get(key);
+  }
+  return new Promise((resolve, reject) => {
+    cp.exec(cmd, {maxBuffer: 1024 * 1024, cwd}, (err, stdout) => {
+      stdout = _(stdout || '')
+        .split(/[\r\n]+/g)
+        .map(_.trim)
+        .filter()
+        .value();
+      if (err) {
+        // reject(err);
+        resolve([]);
+      } else {
+        cache.set(key, stdout);
+        debug('Stdout', stdout);
+        resolve(stdout);
+      }
+    });
+  });
+}
+
+/**
+ * Inspect years for a given file based on git history
+ * @param {string} file - JS/TS file
+ */
+async function getYears(file) {
+  file = file || '.';
+  let dates = await git(
+    process.cwd(),
+    '--no-pager log --pretty=%%ai --all -- %s',
+    file,
+  );
+  debug('Dates for %s', file, dates);
+  if (_.isEmpty(dates)) {
+    // if the given path doesn't have any git history, assume it is new
+    dates = [new Date().toJSON()];
+  } else {
+    dates = [_.head(dates), _.last(dates)];
+  }
+  const years = _.map(dates, getYear);
+  return _.uniq(years).sort();
+}
+
+// assumes ISO-8601 (or similar) format
+function getYear(str) {
+  return str.slice(0, 4);
+}
+
+exports.git = git;
+exports.getYears = getYears;