Implements the new peerDependenciesMeta field

__tests__/fixtures/install/missing-opt-peer-dep/foo/package.json

@@ -2,6 +2,11 @@
   "name": "foo",
   "version": "1.0.0",
   "peerDependencies": {
-    "bar": "optional:*"
+    "bar": "*"
+  },
+  "peerDependenciesMeta": {
+    "bar": {
+      "optional": true
+    }
   }
 }

src/package-linker.js

@@ -595,11 +595,15 @@ export default class PackageLinker {
   resolvePeerModules() {
     for (const pkg of this.resolver.getManifests()) {
       const peerDeps = pkg.peerDependencies;
+      const peerDepsMeta = pkg.peerDependenciesMeta;
+
       if (!peerDeps) {
         continue;
       }
+
       const ref = pkg._reference;
       invariant(ref, 'Package reference is missing');
+
       // TODO: We are taking the "shortest" ref tree but there may be multiple ref trees with the same length
       const refTree = ref.requests.map(req => req.parentNames).sort((arr1, arr2) => arr1.length - arr2.length)[0];
 
@@ -617,8 +621,10 @@ export default class PackageLinker {
       };
 
       for (const peerDepName in peerDeps) {
-        const range = peerDeps[peerDepName].replace(/^optional:/, '');
-        const isOptional = peerDeps[peerDepName].startsWith('optional:');
+        const range = peerDeps[peerDepName];
+        const meta = peerDepsMeta && peerDepsMeta[peerDepName];
+
+        const isOptional = meta && meta.optional ? true : false;
 
         const peerPkgs = this.resolver.getAllInfoForPackageName(peerDepName);
 

src/types.js

@@ -13,6 +13,21 @@ export type CLIFunction = (config: Config, reporter: Reporter, flags: Object, ar
 type _CLIFunctionReturn = boolean;
 export type CLIFunctionReturn = ?_CLIFunctionReturn | Promise<?_CLIFunctionReturn>;
 
+export type DependencyMeta = {
+};
+
+export type DependenciesMeta = {
+  [name: string]: DependencyMeta,
+};
+
+export type PeerDependencyMeta = {
+  optional?: boolean,
+};
+
+export type PeerDependenciesMeta = {
+  [name: string]: DependencyMeta,
+};
+
 // dependency request pattern data structure that's used to request dependencies from a
 // PackageResolver
 export type DependencyRequestPattern = {
@@ -132,6 +147,9 @@ export type Manifest = {
   peerDependencies?: Dependencies,
   optionalDependencies?: Dependencies,
 
+  dependenciesMeta?: DependenciesMeta,
+  peerDependenciesMeta?: PeerDependenciesMeta,
+
   bundleDependencies?: Array<string>,
   bundledDependencies?: Array<string>,