add CI pipeline with lint, test, build

node_modules/exit-x/lib/exit.d.ts

@@ -0,0 +1,8 @@
+/// <reference types="node" />
+
+/**
+ * A replacement for process.exit that ensures stdio are fully drained before exiting.
+ */
+declare function exit(code: number, streams?: [NodeJS.WritableStream, NodeJS.WritableStream]): void;
+
+export = exit;

node_modules/exit-x/lib/exit.js

@@ -0,0 +1,41 @@
+/*
+ * exit
+ * https://github.com/cowboy/node-exit
+ *
+ * Copyright (c) 2013 "Cowboy" Ben Alman
+ * Licensed under the MIT license.
+ */
+
+'use strict';
+
+module.exports = function exit(exitCode, streams) {
+  if (!streams) { streams = [process.stdout, process.stderr]; }
+  var drainCount = 0;
+  // Actually exit if all streams are drained.
+  function tryToExit() {
+    if (drainCount === streams.length) {
+      process.exit(exitCode);
+    }
+  }
+  streams.forEach(function(stream) {
+    // Count drained streams now, but monitor non-drained streams.
+    if (stream.bufferSize === 0) {
+      drainCount++;
+    } else {
+      stream.write('', 'utf-8', function() {
+        drainCount++;
+        tryToExit();
+      });
+    }
+    // Prevent further writing.
+    stream.write = function() {};
+  });
+  // If all streams were already drained, exit now.
+  tryToExit();
+  // In Windows, when run as a Node.js child process, a script utilizing
+  // this library might just exit with a 0 exit code, regardless. This code,
+  // despite the fact that it looks a bit crazy, appears to fix that.
+  process.on('exit', function() {
+    process.exit(exitCode);
+  });
+};