feat(cli): add generic support to cli for workspaces (#9761)

Co-authored-by: DAK <40970507+dakahn@users.noreply.github.com>

Author: joshblack

packages/cli/src/workspace.js

@@ -11,23 +11,26 @@ const execa = require('execa');
 const fs = require('fs-extra');
 const glob = require('fast-glob');
 const path = require('path');
-const packageJson = require('../../../package.json');
-
-const WORKSPACE_ROOT = path.resolve(__dirname, '../../../');
-const packagePaths = glob
-  .sync(packageJson.workspaces.map((pattern) => `${pattern}/package.json`))
-  .map((match) => {
-    const packageJsonPath = path.join(WORKSPACE_ROOT, match);
-    return {
-      packageJsonPath,
-      packageJson: fs.readJsonSync(packageJsonPath),
-      packagePath: path.dirname(packageJsonPath),
-      packageFolder: path.relative(
-        WORKSPACE_ROOT,
-        path.dirname(packageJsonPath)
-      ),
-    };
-  });
+
+const { root: ROOT_DIR } = path.parse(__dirname);
+const WORKSPACE_ROOT = getProjectRoot(__dirname);
+const packageJson = fs.readJsonSync(path.join(WORKSPACE_ROOT, 'package.json'));
+const packagePaths = Array.isArray(packageJson.workspaces)
+  ? glob
+      .sync(packageJson.workspaces.map((pattern) => `${pattern}/package.json`))
+      .map((match) => {
+        const packageJsonPath = path.join(WORKSPACE_ROOT, match);
+        return {
+          packageJsonPath,
+          packageJson: fs.readJsonSync(packageJsonPath),
+          packagePath: path.dirname(packageJsonPath),
+          packageFolder: path.relative(
+            WORKSPACE_ROOT,
+            path.dirname(packageJsonPath)
+          ),
+        };
+      })
+  : [];
 
 const env = {
   root: {
@@ -54,6 +57,53 @@ async function getPackages() {
   return JSON.parse(lernaListOutput).filter((pkg) => !pkg.private);
 }
 
+/**
+ * Returns the root directory of a project, either as a workspace root with a
+ * collection of packages or a single project with a `package.json`
+ * @param {string} directory
+ * @returns {string}
+ */
+function getProjectRoot(directory) {
+  const packageJsonPaths = ancestors(directory).filter((directory) => {
+    return fs.existsSync(path.join(directory, 'package.json'));
+  });
+
+  const rootDirectory =
+    packageJsonPaths.length > 0
+      ? packageJsonPaths[packageJsonPaths.length - 1]
+      : null;
+
+  if (!rootDirectory) {
+    throw new Error(
+      `Unable to find a \`package.json\` file from directory: ${directory}`
+    );
+  }
+
+  return rootDirectory;
+}
+
+/**
+ * Returns an array of the the directory and its ancestors
+ * @param {string} directory
+ * @returns {Array<string>}
+ */
+function ancestors(directory) {
+  const result = [directory];
+  let current = directory;
+
+  while (current !== '') {
+    result.push(current);
+
+    if (current !== ROOT_DIR) {
+      current = path.dirname(current);
+    } else {
+      current = '';
+    }
+  }
+
+  return result;
+}
+
 module.exports = {
   workspace,
   getPackages,