scripts/api-extractor: run prettier on generated API reports

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

scripts/api-extractor.ts

@@ -23,6 +23,7 @@ import {
   dirname,
   join,
 } from 'path';
+import prettier from 'prettier';
 import fs from 'fs-extra';
 import {
   Extractor,
@@ -61,6 +62,27 @@ PackageJsonLookup.prototype.tryGetPackageJsonFilePathFor = function tryGetPackag
   return old.call(this, path);
 };
 
+/**
+ * Another monkey patch where we apply prettier to the API reports. This has to be patched into
+ * the middle of the process as API Extractor does a comparison of the contents of the old
+ * and new files during generation. This inserts the formatting just before that comparison.
+ */
+const {
+  ApiReportGenerator,
+} = require('@microsoft/api-extractor/lib/generators/ApiReportGenerator');
+
+const originalGenerateReviewFileContent =
+  ApiReportGenerator.generateReviewFileContent;
+ApiReportGenerator.generateReviewFileContent = function decoratedGenerateReviewFileContent(
+  ...args
+) {
+  const content = originalGenerateReviewFileContent.apply(this, args);
+  return prettier.format(content, {
+    ...require('@spotify/prettier-config'),
+    parser: 'markdown',
+  });
+};
+
 const PACKAGE_ROOTS = ['packages', 'plugins'];
 
 const SKIPPED_PACKAGES = [