fix(core): performance improvements (#38)

* fix(core): performance improvements

* test for repeating visits

Author: omer-feinberg-island

libs/core/src/true-affected.spec.ts

@@ -459,6 +459,10 @@ describe('trueAffected', () => {
         filePath: 'proj1/index.ts',
         changedLines: [2],
       },
+      {
+        filePath: 'proj2/index.ts',
+        changedLines: [6],
+      },
     ];
     jest.spyOn(git, 'getChangedFiles').mockReturnValue(changedFiles);
 
@@ -512,10 +516,26 @@ describe('trueAffected', () => {
       `Added package proj1 to affected packages for changed line ${changedFiles[0].changedLines[0]} in ${changedFiles[0].filePath}`
     );
     expect(debug).toHaveBeenCalledWith(
-      expect.stringMatching(
-        new RegExp(`^Found identifier .* in .*${changedFiles[0].filePath}$`)
-      )
+      `Added package proj2 to affected packages for changed line ${changedFiles[1].changedLines[0]} in ${changedFiles[1].filePath}`
+    );
+
+    const project1VisitingLogs = debug.mock.calls.filter(
+      ([arg]) => expect.stringMatching(
+        new RegExp(`^Visiting .* in .*${changedFiles[0].filePath}$`)
+      ).asymmetricMatch(arg)
     );
+
+    expect(project1VisitingLogs).toHaveLength(1);
+
+    const project2VisitingLogs = debug.mock.calls.filter(
+      ([arg]) => expect.stringMatching(
+        new RegExp(`^Visiting .* in .*${changedFiles[1].filePath}$`)
+      ).asymmetricMatch(arg)
+    );
+    // would have duplicates if visited multiple times
+    const uniqueProject2VisitingLogs = new Set(project2VisitingLogs.map(([arg]) => arg));
+    expect(uniqueProject2VisitingLogs.size).toBe(project2VisitingLogs.length);
+
     expect(debug).toHaveBeenCalledWith(
       'Added package proj2 to affected packages'
     );

libs/core/src/true-affected.ts

@@ -240,7 +240,7 @@ export const trueAffected = async ({
   }
 
   const affectedPackages = new Set<string>(changedIncludedFilesPackages);
-  const visitedIdentifiers = new Map<string, string[]>();
+  const visitedIdentifiers = new Map<string, Set<string>>();
 
   const findReferencesLibs = (node: Node<ts.Node>) => {
     const rootNode = findRootNode(node);
@@ -269,7 +269,6 @@ export const trueAffected = async ({
     /* istanbul ignore next */
     if (identifier == null) return;
 
-    const refs = identifier.findReferencesAsNodes();
     const identifierName = identifier.getText();
     const path = rootNode.getSourceFile().getFilePath();
 
@@ -278,22 +277,27 @@ export const trueAffected = async ({
     );
 
     if (identifierName && path) {
-      const visited = visitedIdentifiers.get(path) ?? [];
-      if (visited.includes(identifierName)) {
+      if (!visitedIdentifiers.has(path)) {
+        visitedIdentifiers.set(path, new Set());
+      }
+      const visited = visitedIdentifiers.get(path)!;
+      if (visited.has(identifierName)) {
         logger.debug(
           `Already visited ${chalk.bold(identifierName)} in ${chalk.bold(path)}`
         );
 
         return;
       }
 
-      visitedIdentifiers.set(path, [...visited, identifierName]);
+      visited.add(identifierName);
 
       logger.debug(
         `Visiting ${chalk.bold(identifierName)} in ${chalk.bold(path)}`
       );
     }
 
+    const refs = identifier.findReferencesAsNodes();
+
     refs.forEach((node) => {
       const sourceFile = node.getSourceFile();
       const pkg = getPackageNameByPath(sourceFile.getFilePath(), projects);