feat(resolutions): yarn resolutions support added

README.md

@@ -41,3 +41,13 @@ allowing a potential issue to arise if `eslint@4.6.0` was installed and not
 updated before installing. The output also tells you that although the
 _minimum_ allowed version is too low, the _maximum_ allowed version does
 satisfy the `peerDependencies` requirement.
+
+
+If you use resolutions section in your package.json file in order to resolve some unmet peer dependencies
+and want the program to take it into the account run it with include-resolutions option:
+
+```
+> check-peer-deps --include-resolutions=true
+```
+
+Read more about resolutions: https://yarnpkg.com/lang/en/docs/selective-version-resolutions/

__tests__/check-peer-deps.test.js

@@ -40,3 +40,10 @@ test('Finds nothing wrong with no peerDependencies in the tree', async () => {
   expect(output.stdout).toBe('');
   expect(output.stderr).toBe('');
 });
+
+test('Finds nothing wrong with a broken dependency tree backed up with resolutions', async () => {
+  expect.assertions(2);
+  const output = await runCPD(['--include-resolutions=true'], { cwd: path.join(fixtures, 'peerDepWithResolution') });
+  expect(output.stdout).toBe('');
+  expect(output.stderr).toBe('');
+});

__tests__/fixtures/peerDepWithResolution/.gitignore

@@ -0,0 +1 @@
+!node_modules/

__tests__/fixtures/peerDepWithResolution/package.json

@@ -0,0 +1,9 @@
+{
+  "dependencies": {
+    "eslint": "4.9.0",
+    "eslint-config-airbnb-base": "12.1.0"
+  },
+  "resolutions": {
+    "eslint-config-airbnb-base/eslint": "4.0.9"
+  }
+}

check-peer-deps.js

@@ -28,6 +28,11 @@ const optionDefinitions = [
       'peerDependency has been satisfied',
     defaultValue: false,
   },
+  {
+    name: 'include-resolutions',
+    description: 'Check for resolutions section of package.json when checking whether a peerDependency has been satisfied',
+    defaultValue: false,
+  },
   {
     name: 'max-retries',
     description: 'Specify how many retries are allowed for [underline]{npm} commands',
@@ -63,6 +68,7 @@ let options;
 const deps = new Map();
 const npmVers = new Map();
 const peerDeps = new Map();
+const resolutions = new Map();
 
 const log = (value) => {
   if (options.debug) {
@@ -80,6 +86,16 @@ const addDeps = (dependencies) => {
   });
 };
 
+const addResolutions = (res) => {
+  if (!res) {
+    return;
+  }
+  Object.entries(res).forEach((entry) => {
+    const [name, range] = entry;
+    resolutions.set(name, range);
+  });
+};
+
 const readPackageConfig = async (path) => {
   let packageConfig = {};
   try {
@@ -206,6 +222,13 @@ const checkPeerDependencies = async (peerDependencies, name) =>
       }
     }
 
+    if (resolutions.has(`${name}/${peerDepName}`)) {
+      const minAllowedVer = resolutions.get(`${name}/${peerDepName}`);
+      if (semver.satisfies(minAllowedVer, peerDepRange)) {
+        found = true;
+      }
+    }
+
     if (!found) {
       console.error(`A dependency satisfying ${name}'s peerDependency of '${peerDepName}@${peerDepRange}' was not found!`);
 
@@ -232,6 +255,10 @@ const findDependencies = async () => {
   // Get the dependencies to process
   addDeps(packageConfig.dependencies);
 
+  if (options['include-resolutions'] && packageConfig.resolutions) {
+    addResolutions(packageConfig.resolutions);
+  }
+
   if (!options['no-include-dev'] && packageConfig.devDependencies) {
     addDeps(packageConfig.devDependencies);
   }