From afc0c3b23b19d8f082254c3f25e394d6a2cffeae Mon Sep 17 00:00:00 2001
From: goose <tochenyuxiao@163.com>
Date: Sat, 27 Aug 2022 11:21:13 +0800
Subject: [PATCH] feat: basic promise

---
 index.js | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/index.js b/index.js
index 59d6c84..c945c91 100644
--- a/index.js
+++ b/index.js
@@ -1,21 +1,31 @@
+const Status = {
+  PENDING: 'pending',
+  FULFILLED: 'fulfilled',
+  REJECTED: 'rejected'
+}
+
 function myPromise(constructor) {
   let self = this;
 
-  self.status = "pending" //定义状态改变前的初始状态
+  self.status = Status.PENDING //定义状态改变前的初始状态
 
   self.value = undefined;//定义状态为resolved的时候的状态
 
   self.reason = undefined;//定义状态为rejected的时候的状态
 
   function resolve(value) {
-
-    // TODO resolve如何改变状态及返回结果
+    if (self.status === Status.PENDING) {
+      self.status = Status.FULFILLED
+      self.value = value
+    }
 
   }
 
   function reject(reason) {
-
-    // TODO reject如何改变状态及返回结果
+    if (self.status === Status.PENDING) {
+      self.status = Status.REJECTED
+      self.reason = reason
+    }
 
   }
 
@@ -34,8 +44,12 @@ function myPromise(constructor) {
 }
 
 myPromise.prototype.then = function (onFullfilled, onRejected) {
+  if (this.status === Status.FULFILLED) {
+    onFullfilled?.(this.value)
+  } else if (this.status === Status.REJECTED) {
+    onRejected?.(this.reason)
+  }
 
-  //TODO then如何实现
 
 }
 module.exports = myPromise