fix: stops failure on npm <v7 with peer deps

lib/parsers/index.ts

@@ -6,6 +6,7 @@ import { Yarn2Lock } from './yarn2-lock-parser';
 export interface Dep {
   name: string;
   version: string;
+  isPeerDep?: boolean;
   dev?: boolean;
 }
 
@@ -105,7 +106,6 @@ export function getTopLevelDeps(
   const dependenciesIterator = Object.entries({
     ...targetFile.dependencies,
     ...(includeDev ? targetFile.devDependencies : null),
-    ...(targetFile.peerDependencies || {}),
     ...(targetFile.optionalDependencies || {}),
   });
 
@@ -120,6 +120,16 @@ export function getTopLevelDeps(
     });
   }
 
+  if (targetFile.peerDependencies) {
+    for (const [name, version] of Object.entries(targetFile.peerDependencies)) {
+      dependencies.push({
+        name,
+        version,
+        isPeerDep: true,
+      });
+    }
+  }
+
   return dependencies;
 }
 

lib/parsers/lock-parser-base.ts

@@ -23,6 +23,7 @@ import {
   OutOfSyncError,
   TreeSizeLimitError,
 } from '../errors';
+import { PackageLock } from './package-lock-parser';
 
 export interface PackageLockDeps {
   [depName: string]: PackageLockDep;
@@ -148,6 +149,8 @@ export abstract class LockParserBase implements LockfileParser {
       } else if (/^file:/.test(dep.version)) {
         depTree.dependencies[dep.name] = createDepTreeDepFromDep(dep);
         treeSize++;
+      } else if (isPeerDepInLockfileV1(lockfile, dep)) {
+        continue;
       } else {
         // TODO: also check the package version
         // for a stricter check
@@ -417,3 +420,11 @@ export abstract class LockParserBase implements LockfileParser {
     throw new Error('Not implemented');
   }
 }
+
+// Checks for the case of using npm version 6 or less
+// in conjunction with peer deps. This is needed as npm 6
+// does not auto install peerDeps so we dont need to worry
+// about them.
+function isPeerDepInLockfileV1(lockfile: Lockfile, dep: Dep) {
+  return (lockfile as PackageLock).lockfileVersion === 1 && dep.isPeerDep;
+}

test/lib/fixtures/peer-deps/npm6/expected-tree.json

@@ -0,0 +1,31 @@
+{
+  "dependencies": {
+    "adm-zip": {
+      "labels": {
+        "scope": "prod"
+      },
+      "name": "adm-zip",
+      "version": "0.4.7"
+    },
+    "debug": {
+      "labels": {
+        "scope": "prod"
+      },
+      "name": "debug",
+      "version": "2.6.9",
+      "dependencies": {
+        "ms": {
+          "labels": {
+            "scope": "prod"
+          },
+          "name": "ms",
+          "version": "2.0.0"
+        }
+      }
+    }
+  },
+  "hasDevDependencies": false,
+  "name": "goof",
+  "size": 4,
+  "version": "0.0.3"
+}

test/lib/fixtures/peer-deps/npm7/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "goof",
+  "version": "0.0.3",
+  "dependencies": {
+    "adm-zip": "0.4.7"
+  },
+  "peerDependencies": {
+    "has": "^1.0.0"
+  },
+  "optionalDependencies": {
+    "debug": "^2.2.0"
+  }
+}

test/lib/package-lock-depTree.test.ts

@@ -254,11 +254,22 @@ test('`package.json` with file as version', async (t) => {
   t.deepEqual(depTree, expectedDepTree, 'Tree generated as expected');
 });
 
+test('`package.json` with peer and optionals (npm6)', async (t) => {
+  const expectedDepTree = load('peer-deps/npm6/expected-tree.json');
+
+  const depTree = await buildDepTreeFromFiles(
+    `${__dirname}/fixtures/peer-deps/npm6`,
+    'package.json',
+    'package-lock.json',
+  );
+
+  t.deepEqual(depTree, expectedDepTree, 'Tree generated as expected');
+});
 test('`package.json` with peer and optionals (npm7)', async (t) => {
-  const expectedDepTree = load('peer-deps/expected-tree.json');
+  const expectedDepTree = load('peer-deps/npm7/expected-tree.json');
 
   const depTree = await buildDepTreeFromFiles(
-    `${__dirname}/fixtures/peer-deps/`,
+    `${__dirname}/fixtures/peer-deps/npm7`,
     'package.json',
     'package-lock.json',
   );