fix(core): update

ts/tswatch.classes.watcher.ts

@@ -0,0 +1,97 @@
+import * as plugins from './tswatch.plugins';
+import { logger } from './tswatch.logging';
+
+export interface IWatcherConstructorOptions {
+  filePathToWatch: string;
+  commandToExecute: string;
+  timeout?: number;
+}
+
+/**
+ * A watcher keeps track of one child execution
+ */
+export class Watcher {
+  private smartshellInstance = new plugins.smartshell.Smartshell({
+    executor: 'bash'
+  });
+  private currentExecution: plugins.smartshell.IExecResultStreaming;
+  private smartchokWatcher = new plugins.smartchok.Smartchok([], {});
+  private options: IWatcherConstructorOptions;
+
+  constructor(optionsArg: IWatcherConstructorOptions) {
+    this.options = optionsArg;
+  }
+
+  /**
+   * start the file
+   */
+  public async start() {
+    this.setupCleanup();
+    console.log(`Looking at ${this.options.filePathToWatch} for changes`);
+    this.smartchokWatcher.add([this.options.filePathToWatch]); // __dirname refers to the directory of this very file
+    await this.smartchokWatcher.start();
+    const changeObservable = await this.smartchokWatcher.getObservableFor('change');
+    changeObservable.subscribe(() => {
+      this.updateCurrentExecution();
+    });
+    this.updateCurrentExecution();
+  }
+
+  /**
+   * updates the current execution
+   */
+  private async updateCurrentExecution() {
+    if (this.currentExecution) {
+      logger.log('ok', `reexecuting ${this.options.commandToExecute}`);
+      process.kill(-this.currentExecution.childProcess.pid);
+    } else {
+      logger.log('ok', `executing ${this.options.commandToExecute} for the first time`);
+    }
+    this.currentExecution = await this.smartshellInstance.execStreaming(
+      this.options.commandToExecute
+    );
+    this.currentExecution = null;
+  }
+
+  /**
+   * this method sets up a clean exit strategy
+   */
+  private async setupCleanup() {
+    const cleanup = () => {
+      if (this.currentExecution) {
+        process.kill(-this.currentExecution.childProcess.pid);
+      }
+    };
+    process.on('exit', () => {
+      console.log('');
+      console.log('now exiting!');
+      cleanup();
+      process.exit(0);
+    });
+    process.on('SIGINT', () => {
+      console.log('');
+      console.log('ok! got SIGINT We are exiting! Just cleaning up to exit neatly :)');
+      cleanup();
+      process.exit(0);
+    });
+
+    // handle timeout
+    if (this.options.timeout) {
+      plugins.smartdelay.delayFor(this.options.timeout).then(() => {
+        console.log(`timed out afer ${this.options.timeout} milliseconds! exiting!`);
+        cleanup();
+        process.exit(0);
+      });
+    }
+  }
+  
+  /**
+   * stops the watcher
+   */
+  public async stop() {
+    await this.smartchokWatcher.stop();
+    if (this.currentExecution) {
+      process.kill(-this.currentExecution.childProcess.pid);
+    }
+  }
+}