Expose data/helpers to check for no changes in bundle sizes to reduce noise

tools/bundle-size-tools/src/ADO/AdoSizeComparator.ts

@@ -6,6 +6,7 @@
 import { WebApi } from 'azure-devops-node-api';
 import JSZip from 'jszip';
 import { join } from 'path';
+import { BundleComparison, BundleComparisonResult } from '../BundleBuddyTypes';
 import { getBaselineCommit, getBuilds, getPriorCommit } from '../utilities';
 import { BuildStatus, BuildResult } from 'azure-devops-node-api/interfaces/BuildInterfaces';
 import { IADOConstants } from './Constants';
@@ -75,9 +76,10 @@ export class ADOSizeComparator {
    * Create a size comparison message that can be posted to a PR
    * @param tagWaiting - If the build should be tagged to be updated when the baseline
    * build completes (if it wasn't already complete when the comparison runs)
-   * @returns The size comparison message
+   * @returns The size comparison result with formatted message and raw data.  In case
+   * of failure, the message contains the error message and the raw data will be undefined.
    */
-  public async createSizeComparisonMessage(tagWaiting: boolean): Promise<string> {
+  public async createSizeComparisonMessage(tagWaiting: boolean): Promise<BundleComparisonResult> {
     let baselineCommit: string | undefined = getBaselineCommit();
     console.log(`The baseline commit for this PR is ${baselineCommit}`);
 
@@ -103,7 +105,7 @@ export class ADOSizeComparator {
       if (baselineBuild.id === undefined) {
         const message = `Baseline build does not have a build id`;
         console.log(message);
-        return message;
+        return { message, comparison: undefined };
       }
 
       // Baseline build is pending
@@ -115,7 +117,7 @@ export class ADOSizeComparator {
           this.tagBuildAsWaiting(baselineCommit);
         }
 
-        return message;
+        return { message, comparison: undefined };
       }
 
       // Baseline build failed
@@ -125,7 +127,7 @@ export class ADOSizeComparator {
           baselineCommit
         );
         console.log(message);
-        return message;
+        return { message, comparison: undefined };
       }
 
       // Baseline build succeeded
@@ -153,12 +155,16 @@ export class ADOSizeComparator {
     if (baselineCommit === undefined || baselineZip === undefined) {
       const message = `Could not find a usable baseline build with search starting at CI ${getBaselineCommit()}`;
       console.log(message);
-      return message;
+      return { message, comparison: undefined };
     }
 
-    const message = await this.createMessageFromZip(baselineCommit, baselineZip);
+    const comparison: BundleComparison[] = await this.createComparisonFromZip(baselineCommit, baselineZip);
+    console.log(JSON.stringify(comparison));
+
+    const message = getCommentForBundleDiff(comparison, baselineCommit);
     console.log(message);
-    return message;
+
+    return { message, comparison };
   }
 
   private async tagBuildAsWaiting(baselineCommit: string): Promise<void> {
@@ -173,7 +179,7 @@ export class ADOSizeComparator {
     }
   }
 
-  private async createMessageFromZip(baselineCommit: string, baselineZip: JSZip): Promise<string> {
+  private async createComparisonFromZip(baselineCommit: string, baselineZip: JSZip): Promise<BundleComparison[]> {
     const baselineZipBundlePaths = getBundlePathsFromZipObject(baselineZip);
 
     const prBundleFileSystemPaths = await getBundlePathsFromFileSystem(this.localReportPath);
@@ -198,11 +204,6 @@ export class ADOSizeComparator {
       statsProcessors: DefaultStatsProcessors
     });
 
-    const bundleComparisons = compareBundles(baselineSummaries, prSummaries);
-
-    console.log(JSON.stringify(bundleComparisons));
-
-    const message = getCommentForBundleDiff(bundleComparisons, baselineCommit);
-    return message;
+    return compareBundles(baselineSummaries, prSummaries);
   }
 }

tools/bundle-size-tools/src/BundleBuddyTypes.ts

@@ -32,6 +32,15 @@ export interface BundleComparison {
   commonBundleMetrics: { [key: string]: { baseline: BundleMetric; compare: BundleMetric } };
 }
 
+/**
+ * The formatted message string of a bundle comparison along with the
+ * comparison data itself
+ */
+export type BundleComparisonResult = {
+  message: string,
+  comparison: BundleComparison[] | undefined,
+};
+
 /**
  * Functions used to process a webpack stats file and produce a set of metrics. Some processors may choose
  * to work off a bundle specific config file. Note that these config files are optional, so not all bundles

tools/bundle-size-tools/src/compareBundles.ts

@@ -37,3 +37,22 @@ export function compareBundles(baseline: BundleSummaries, compare: BundleSummari
 
   return results;
 }
+
+/**
+ * Checks if a bundle comparison contains no size changes
+ * @param comparisons
+ */
+export function bundlesContainNoChanges(comparisons: BundleComparison[]): boolean {
+  for (let i = 0; i < comparisons.length; i++) {
+    const { commonBundleMetrics } = comparisons[i];
+    let metrics = Object.entries(commonBundleMetrics);
+    for (let j = 0; j < metrics.length; j++) {
+      const [ , { baseline, compare }] = metrics[j];
+      if (baseline.parsedSize !== compare.parsedSize) {
+        return false;
+      }
+    }
+  }
+
+  return true;
+}