feat(mf): respect APF v14 for discovering secondaries

before, the folders of the shared packages have been
searched for subfolders with a package.json. These
subfolders were added as secondary entry points.

Now, if the package.json contains an exports field,
like defined by APF v14, this field is used to find
out about secondary entry points. If this is not
the case, the original logic described aboved is
used as a fallback.

libs/mf/src/utils/share-utils.ts

@@ -13,6 +13,11 @@ export const DEFAULT_SKIP_LIST = [
     'zone.js'
 ];
 
+export const DEFAULT_SECONARIES_SKIP_LIST = [
+    '@angular/router/upgrade', 
+    '@angular/common/upgrade'
+];
+
 type VersionMap = Record<string, string>;
 type IncludeSecondariesOptions = { skip: string | string[] } | boolean;
 type CustomSharedConfig =  SharedConfig & { includeSecondaries?: IncludeSecondariesOptions };
@@ -80,7 +85,7 @@ function lookupVersion(key: string, versions: VersionMap): string {
     return versions[key];
 }
 
-function _findSecondaries(libPath: string, excludes: string[], acc: string[]): void {
+function _findSecondaries(libPath: string, excludes: string[], shareObject: SharedConfig, acc: Record<string, SharedConfig>): void {
 
     const files = fs.readdirSync(libPath);
 
@@ -94,19 +99,19 @@ function _findSecondaries(libPath: string, excludes: string[], acc: string[]): v
         if (excludes.includes(secondaryLibName)) {
             continue;
         }
-        acc.push(secondaryLibName);
-        _findSecondaries(s, excludes, acc);
+        acc[secondaryLibName] = {...shareObject};
+        _findSecondaries(s, excludes, shareObject, acc);
     }
 }
 
-function findSecondaries(libPath: string, excludes: string[]): string[] {
-    const acc = [];
-    _findSecondaries(libPath, excludes, acc);
+function findSecondaries(libPath: string, excludes: string[], shareObject: SharedConfig): Record<string, SharedConfig> {
+    const acc = {} as Record<string, SharedConfig>;
+    _findSecondaries(libPath, excludes, shareObject, acc);
     return acc;
 }
 
-function getSecondaries(includeSecondaries: IncludeSecondariesOptions, packagePath: string, key: string): string[] {
-    let exclude = [];
+function getSecondaries(includeSecondaries: IncludeSecondariesOptions, packagePath: string, key: string, shareObject: SharedConfig): Record<string, SharedConfig> {
+    let exclude = [...DEFAULT_SECONARIES_SKIP_LIST];
 
     if (typeof includeSecondaries === 'object' ) {
         if (Array.isArray(includeSecondaries.skip)) {
@@ -119,14 +124,54 @@ function getSecondaries(includeSecondaries: IncludeSecondariesOptions, packagePa
 
     const libPath = path.join(path.dirname(packagePath), 'node_modules', key);
 
-    const secondaries = findSecondaries(libPath, exclude);
+    const configured = readConfiguredSecondaries(key, libPath, exclude, shareObject);
+    if (configured) {
+        return configured;
+    }
+
+    // Fallback: Search folders
+    const secondaries = findSecondaries(libPath, exclude, shareObject);
     return secondaries;
 }
 
-function addSecondaries(secondaries: string[], result: Config, shareObject: Config): void {
-    for (const s of secondaries) {
-        result[s] = shareObject;
+function readConfiguredSecondaries(parent: string, libPath: string, exclude: string[], shareObject: SharedConfig): Record<string, SharedConfig> {
+    const libPackageJson = path.join(libPath, 'package.json');
+
+    if (!fs.existsSync(libPackageJson)) {
+        return null;
     }
+
+    const packageJson = JSON.parse(fs.readFileSync(libPackageJson, 'utf-8'));
+    const exports = packageJson['exports'] as Record<string, Record<string, string>>;
+
+    if (!exports) {
+        return null;
+    }
+
+    const keys = Object.keys(exports)
+        .filter(key => key != '.'
+                    && key != './package.json' 
+                    && !key.endsWith('*')
+                    && exports[key]['default']);
+
+    const result = {} as Record<string, SharedConfig>;
+
+    for(const key of keys) {
+        const relPath = exports[key]['default'];
+        const secondaryName = path.join(parent, key).replace(/\\/g, '/');
+
+        if (exclude.includes(secondaryName)) {
+            continue;
+        }
+
+        result[secondaryName] = {
+            ...shareObject,
+            import: path.join(libPath, relPath)
+        }
+    }
+
+    return result;
+
 }
 
 export function shareAll(config: CustomSharedConfig = {}, skip: string[] = DEFAULT_SKIP_LIST, packageJsonPath = ''): Config {
@@ -174,7 +219,9 @@ export function share(shareObjects: Config, packageJsonPath = ''): Config {
         const shareObject = shareObjects[key];
 
         if (shareObject.requiredVersion === 'auto' || (inferVersion && typeof shareObject.requiredVersion === 'undefined')) {
-            shareObject.requiredVersion = lookupVersion(key, versions);
+            const version = lookupVersion(key, versions);
+            shareObject.requiredVersion = version;
+            shareObject.version = version.replace(/^\D*/, '');
         }
 
         if (typeof shareObject.includeSecondaries === 'undefined') {
@@ -189,11 +236,17 @@ export function share(shareObjects: Config, packageJsonPath = ''): Config {
         result[key] = shareObject;
 
         if (includeSecondaries) {
-            const secondaries = getSecondaries(includeSecondaries, packagePath, key);
-            addSecondaries(secondaries, result, shareObject);
+            const secondaries = getSecondaries(includeSecondaries, packagePath, key, shareObject);
+            addSecondaries(secondaries, result);
         }
 
     }
 
     return result;
 }
+function addSecondaries(secondaries: Record<string, SharedConfig>, result: {}) {
+    for (const key in secondaries) {
+        result[key] = secondaries[key];
+    }
+}
+