diff --git a/.github/workflows/pr-checks.yml b/.github/workflows/pr-checks.yml
index ac61475d6..d835d15ed 100644
--- a/.github/workflows/pr-checks.yml
+++ b/.github/workflows/pr-checks.yml
@@ -55,7 +55,7 @@ jobs:
           npm ci
 
       - name: Verify compiled JS up to date
-        run: .github/workflows/script/check-js.sh
+        run: npx tsx pr-checks/check-js.ts
 
       - name: Run unit tests
         if: always()
diff --git a/.github/workflows/script/check-js.sh b/.github/workflows/script/check-js.sh
deleted file mode 100755
index 57638dcf2..000000000
--- a/.github/workflows/script/check-js.sh
+++ /dev/null
@@ -1,33 +0,0 @@
-#!/bin/bash
-set -eu
-
-# Sanity check that repo is clean to start with
-if [ ! -z "$(git status --porcelain)" ]; then
-    # If we get a fail here then this workflow needs attention...
-    >&2 echo "Failed: Repo should be clean before testing!"
-    exit 1
-fi
-# Wipe the lib directory in case there are extra unnecessary files in there
-rm -rf lib
-# Generate the JavaScript files
-npm run-script build
-# Check that repo is still clean
-if [ ! -z "$(git status --porcelain)" ]; then
-    # If we get a fail here then the PR needs attention
-    >&2 echo "Failed: JavaScript files are not up to date. Run 'rm -rf lib && npm run-script build' to update"
-    git status
-
-    echo "### Transpiled JS diff" >> $GITHUB_STEP_SUMMARY
-    echo "" >> $GITHUB_STEP_SUMMARY
-    echo '```diff' >> $GITHUB_STEP_SUMMARY
-    git diff --output="$RUNNER_TEMP/js.diff"
-    cat "$RUNNER_TEMP/js.diff" >> $GITHUB_STEP_SUMMARY
-    echo '```' >> $GITHUB_STEP_SUMMARY
-
-    # Reset bundled files to allow other checks to test for changes
-    git checkout lib
-
-    # Fail this check
-    exit 1
-fi
-echo "Success: JavaScript files are up to date"
diff --git a/pr-checks/check-js.ts b/pr-checks/check-js.ts
new file mode 100755
index 000000000..835bb0056
--- /dev/null
+++ b/pr-checks/check-js.ts
@@ -0,0 +1,67 @@
+#!/usr/bin/env npx tsx
+
+import * as fs from "node:fs";
+import * as path from "node:path";
+
+import * as core from "@actions/core";
+
+import { runCommand, runGit } from "./command";
+import { LIB_ROOT, PR_CHECKS_DIR, REPO_ROOT } from "./config";
+import { getErrorMessage } from "./util";
+
+function main() {
+  // Sanity check that repo is clean to start with
+  try {
+    runGit(["diff", "--exit-code"], { allowNonZeroExitCode: false });
+    console.info("Repository is clean.");
+  } catch (err) {
+    // If we get a fail here then this workflow needs attention...
+    console.error(getErrorMessage(err));
+    console.error("Failed: Repo should be clean before testing!");
+    return -1;
+  }
+
+  // Wipe the lib directory in case there are extra unnecessary files in there
+  console.info(`Removing ${LIB_ROOT}...`);
+  fs.rmSync(LIB_ROOT, { recursive: true, force: true });
+
+  // Generate the JavaScript files
+  runCommand("npm", ["run", "build"], { execOptions: { shell: true } });
+
+  // Check that repo is still clean
+  try {
+    runGit(["diff", "--exit-code"], { allowNonZeroExitCode: false });
+    console.info("Repository is clean.");
+  } catch (err) {
+    // If we get a fail here then the PR needs attention
+    console.error(getErrorMessage(err));
+    console.error("Failed: JavaScript files are not up to date.");
+    console.error("Run 'rm -rf lib && npm run build' to update.");
+
+    const diffFile = path.join(
+      process.env["RUNNER_TEMP"] ?? PR_CHECKS_DIR,
+      "js.diff",
+    );
+    runCommand("git", ["status"]);
+    runCommand("git", ["diff", `--output=${diffFile}`], {
+      execOptions: { cwd: REPO_ROOT },
+    });
+
+    core.summary.addHeading("Transpiled JS diff", 3);
+    core.summary.addCodeBlock(fs.readFileSync(diffFile, "utf-8"), "diff");
+
+    fs.rmSync(diffFile);
+
+    // Reset bundled files to allow other checks to test for changes
+    runCommand("git", ["checkout", "lib"]);
+
+    return 1;
+  }
+
+  console.info("Success: JavaScript files are up to date");
+  return 0;
+}
+
+if (require.main === module) {
+  process.exit(main());
+}
diff --git a/pr-checks/config.ts b/pr-checks/config.ts
index 9cd23e48d..40ca7037a 100644
--- a/pr-checks/config.ts
+++ b/pr-checks/config.ts
@@ -24,6 +24,9 @@ export const BUNDLE_METADATA_FILE = path.join(REPO_ROOT, "meta.json");
 /** The `src` directory. */
 export const SOURCE_ROOT = path.join(REPO_ROOT, "src");
 
+/** The `src` directory. */
+export const LIB_ROOT = path.join(REPO_ROOT, "lib");
+
 /** The path to `defaults.json`. */
 export const DEFAULTS_FILE = path.join(SOURCE_ROOT, "defaults.json");