Tolerate missing optional dependencies

src/PackageJson.js

@@ -14,7 +14,7 @@ module.exports = class PackageJson {
 
  forEachDependencySet(fn) {
  ['dependencies', 'devDependencies', 'peerDependencies', 'optionalDependencies'].forEach((key) => {
- fn(this.#source[key] || {});
+ fn(this.#source[key] || {}, key);
  });
  }
 };

src/rules/latest.js

@@ -42,14 +42,15 @@ const rule = {
  const { text } = context.getSourceCode();
  const packageJson = new PackageJson(text);
 
- packageJson.forEachDependencySet((dependencies) => {
+ packageJson.forEachDependencySet((dependencies, set) => {
  Object.keys(dependencies).forEach((dependency) => {
 
  if (!packages.includes(dependency)) return;
  if (isUrl(dependencies[dependency])) return;
 
  const installed = getInstalledPackage(npmOptions, dependency);
- if (!installed || installed.missing) {
+ if (!installed?.version || installed.missing) {
+ if (set === 'optionalDependencies') return;
  context.report({ node, messageId: 'missing', data: { dependency } });
  return;
  }

test/fixtures/latest/package.json

@@ -8,5 +8,8 @@
  "lodash": "latest",
  "oubliette": "1.0.4",
  "zunit": "latest"
+ },
+ "optionalDependencies": {
+ "missing": "1.0.0"
  }
 }

test/latest.test.js

@@ -128,13 +128,31 @@ describe('latest', () => {
  expect(results[0]).toHaveProperty('warningCount', 0);
  });
 
+ it('should tolerate missing optional packages', async () => {
+ const results = await createLinter({
+ 'tech-radar/latest': [
+ 'error',
+ {
+ packages: [
+ 'missing',
+ ],
+ cwd,
+ },
+ ],
+ }).lintFiles('package.json');
+
+ expect(results).toHaveLength(1);
+ expect(results[0]).toHaveProperty('errorCount', 0);
+ expect(results[0]).toHaveProperty('warningCount', 0);
+ });
+
  describe('latest-missing', () => {
 
  beforeEach(() => {
  cwd = path.resolve(__dirname, 'fixtures', 'latest-missing');
  });
 
- it('should report missing packages', async () => {
+ it('should report missing, mandatory packages', async () => {
  const results = await createLinter({
  'tech-radar/latest': [
  'error',