add ensure-workspaces rule

README.md

@@ -55,6 +55,7 @@ eslint . --ext js,json
 |:--------|:------------|
 | [json-files/ensure-repository-directory](./docs/rules/ensure-repository-directory.md) | ensure repository/directory in package.json |
 | [json-files/ensure-volta-extends](./docs/rules/ensure-volta-extends.md) | ensure volta-extends in package.json |
+| [json-files/ensure-workspaces](./docs/rules/ensure-workspaces.md) | ensure workspace globs in package.json resolve to directories |
 | [json-files/eol-last](./docs/rules/eol-last.md) | require or disallow newline at the end of package.json |
 | [json-files/no-branch-in-dependencies](./docs/rules/no-branch-in-dependencies.md) | prevent branches in package.json dependencies |
 | [json-files/require-engines](./docs/rules/require-engines.md) | require the engines field in package.json |

docs/rules/ensure-workspaces.md

@@ -0,0 +1,58 @@
+# Ensure workspace globs in package.json resolve to directories (ensure-workspaces)
+
+Check that the monorepo workspace globs find dirs with package.json files.
+
+
+## Rule Details
+
+This rule aims to ensure the workspace globs find dirs with package.json files.
+
+Examples of **incorrect** code for this rule:
+
+```json
+{
+  "workspace": [
+    "packages/*/missing-dir"
+  ]
+}
+```
+
+Examples of **correct** code for this rule:
+
+```json
+{
+  "workspace": [
+    "packages/*/dir-with-package-json"
+  ]
+}
+```
+
+```json
+{
+  "workspace": [
+    "packages/dir-with-package-json"
+  ]
+}
+```
+
+```json
+{
+  "workspace": {
+    "packages": [
+      "packages/*/dir-with-package-json"
+    ]
+  }
+}
+```
+
+### Options
+
+
+
+## When Not To Use It
+
+If workspace globs are placeholders for future packages.
+
+## Further Reading
+
+https://docs.npmjs.com/cli/v10/configuring-npm/package-json#workspaces

lib/rules/ensure-workspaces.js

@@ -0,0 +1,68 @@
+'use strict';
+
+const path = require('path');
+const fg = require('fast-glob');
+
+module.exports = {
+  meta: {
+    docs: {
+      description: 'ensure workspace globs in package.json resolve to directories'
+    },
+    schema: [
+    ]
+  },
+
+  create(context) {
+    let filename = context.getFilename();
+    if (path.basename(filename) !== 'package.json') {
+      return {};
+    }
+
+    return {
+      AssignmentExpression(node) {
+        let json = node.right;
+        let property = json.properties.find(p => p.key.value === 'workspaces');
+        if (!property) {
+          return;
+        }
+
+        let workspaces = property.value;
+        if (workspaces.type === 'ObjectExpression') {
+          let property = workspaces.properties.find(p => p.key.value === 'packages');
+          if (!property) {
+            return;
+          }
+
+          workspaces = property.value;
+        }
+
+        if (workspaces.type !== 'ArrayExpression') {
+          return;
+        }
+
+        for (let node of workspaces.elements) {
+          if (node.type !== 'Literal') {
+            continue;
+          }
+
+          if (typeof node.value !== 'string') {
+            continue;
+          }
+
+          let glob = path.join(node.value, 'package.json');
+
+          let entries = fg.sync(glob, {
+            cwd: path.dirname(filename)
+          });
+
+          if (!entries.length) {
+            context.report({
+              node,
+              message: 'workspace path/glob does not match any workspaces with a package.json.'
+            });
+          }
+        }
+      }
+    };
+  }
+};

package.json

@@ -20,6 +20,7 @@
   "dependencies": {
     "ajv": "^8.2.0",
     "better-ajv-errors": "^1.2.0",
+    "fast-glob": "^3.3.2",
     "requireindex": "^1.2.0",
     "semver": "^7.0.0",
     "sort-package-json": "^1.22.1"

tests/fixtures/workspaces/foo/bar/package.json

@@ -0,0 +1 @@
+{}