completed homework2

lib/db.js

@@ -1,13 +1,44 @@
-const Tapable = require('tapable')
+const {
+  AsyncParallelBailHook,
+  SyncHook,
+  SyncWaterfallHook,
+} = require("tapable");
 
-class DB extends Tapable {
-  constructor() {
-    // TODO
+class DB {
+  constructor(options = {}) {
+    this.options = options;
+    this.hooks = {
+      endpointHook: new AsyncParallelBailHook(["options"]),
+      optionHook: new SyncHook(["options"]),
+      judgeHook: new SyncWaterfallHook(["res"]),
+    };
   }
 
-  request() {
-    // TODO
+  plugin(name, cb) {
+    if (name === "endpoint") {
+      this.hooks.endpointHook.tapPromise(
+        name,
+        async (options) => await cb(options)
+      );
+    } else if (name === "options") {
+      this.hooks.optionHook.tap(name, cb);
+    } else if (name === "judge") {
+      this.hooks.judgeHook.tap(name, cb);
+    }
+  }
+
+  async request(options = {}) {
+    this.options = Object.assign({}, this.options, options);
+
+    this.hooks.optionHook.call(this.options);
+    const result = await this.hooks.endpointHook.promise(this.options);
+
+    if (this.hooks.judgeHook.call(result) === true || result === undefined) {
+      return Promise.reject(result);
+    }
+
+    return result;
   }
 }
 
-module.exports = DB
+module.exports = DB;

package.json

@@ -28,6 +28,7 @@
     "webpack": "^3.5.3"
   },
   "dependencies": {
-    "puppeteer": "^16.2.0"
+    "puppeteer": "^16.2.0",
+    "tapable": "^2.2.1"
   }
 }