add cancelable Timeout

ts/index.ts

@@ -1,13 +1,44 @@
 import 'typings-global'
+import * as smartq from 'smartq'
 
+/**
+ * delay something, works like setTimeout
+ * @param timeInMillisecond
+ * @param passOn
+ */
 export let delayFor = async <T>(timeInMillisecond: number, passOn?: T) => {
-    await new Promise((resolve, reject) => {
-        setTimeout(
-            () => {
-                resolve()
-            },
-            timeInMillisecond
-        )
-    })
-    return passOn
+  await new Promise((resolve, reject) => {
+    setTimeout(
+      () => {
+        resolve()
+      },
+      timeInMillisecond
+    )
+  })
+  return passOn
+}
+
+export class Timeout<T> {
+  promise: Promise<T>
+  private _deferred: smartq.Deferred<T>
+  private _timeout: any
+  private _cancelled: boolean = false
+  constructor (timeInMillisecondArg, passOn?: T) {
+    this._deferred = smartq.defer<T>()
+    this.promise = this._deferred.promise
+    this._timeout = setTimeout(() => {
+      if (!this._cancelled) {
+        this._deferred.resolve(passOn)
+      }
+    }, timeInMillisecondArg)
+  }
+
+  makeUnrefed () {
+    this._timeout.unref()
+  }
+
+  cancel () {
+    this._cancelled = true
+    this.makeUnrefed()
+  }
 }