feat: use stream class to replace EventEmitter.

#35

lib/mm.js

@@ -7,6 +7,8 @@ const https = require('https');
 const cp = require('child_process');
 const semver = require('semver');
 const thenify = require('thenify').withCallback;
+const Readable = require('stream').Readable;
+const Duplex = require('stream').Duplex;
 
 const mock = module.exports = function mock() {
   return muk.apply(null, arguments);
@@ -213,9 +215,10 @@ function matchURL(options, params) {
 }
 
 function mockRequest() {
-  const req = new EventEmitter();
-  req.write = function() {};
-  req.end = function() {};
+  const req = new Duplex({
+    write() {},
+    read() {},
+  });
   req.abort = function() {
     req._aborted = true;
     process.nextTick(function() {
@@ -312,7 +315,27 @@ function _request(mod, url, data, headers, delay) {
     if (stream) {
       res = stream;
     } else {
-      res = new EventEmitter();
+      res = new Readable({
+        read() {
+          let chunk = datas.shift();
+          if (!chunk) {
+            if (!req._aborted) {
+              this.push(null);
+            }
+            return;
+          }
+
+          if (!req._aborted) {
+            if (typeof chunk === 'string') {
+              chunk = new Buffer(chunk);
+            }
+            if (this.charset) {
+              chunk = chunk.toString(this.charset);
+            }
+            this.push(chunk);
+          }
+        },
+      });
       res.setEncoding = function(charset) {
         res.charset = charset;
       };
@@ -321,34 +344,9 @@ function _request(mod, url, data, headers, delay) {
     res.statusCode = headers.statusCode || 200;
     res.headers = omit(headers, 'statusCode');
 
-    const ondata = function() {
-      let chunk = datas.shift();
-      if (!chunk) {
-        if (!req._aborted) {
-          res.emit('end');
-        }
-        return;
-      }
-
-      if (!req._aborted) {
-        if (typeof chunk === 'string') {
-          chunk = new Buffer(chunk);
-        }
-        if (res.charset) {
-          chunk = chunk.toString(res.charset);
-        }
-        res.emit('data', chunk);
-      }
-      process.nextTick(ondata);
-    };
-
     setTimeout(function() {
       if (!req._aborted) {
         req.emit('response', res);
-        if (stream) {
-          return;
-        }
-        process.nextTick(ondata);
       }
     }, delay);
 
@@ -421,7 +419,10 @@ function _requestError(mod, url, reqError, resError, delay) {
         return req.emit('error', reqError);
       }
 
-      const res = new EventEmitter();
+      const res = new Duplex({
+        read() {},
+        write() {},
+      });
       res.statusCode = 200;
       res.headers = {
         server: 'MockMateServer',