mock.js改造兼容支持异步函数

李恒道

下断点找一下，可以发现调用我们自己的mock函数处于

        if (this.custom.async) setTimeout(done, this.custom.timeout) // 异步
            else done() // 同步

            function done() {
                that.readyState = MockXMLHttpRequest.HEADERS_RECEIVED
                that.dispatchEvent(new Event('readystatechange' /*, false, false, that*/ ))
                that.readyState = MockXMLHttpRequest.LOADING
                that.dispatchEvent(new Event('readystatechange' /*, false, false, that*/ ))

                that.status = 200
                that.statusText = HTTP_STATUS_CODES[200]

                // fix #92 #93 by @qddegtya
                that.response = that.responseText = JSON.stringify(
                    convert(that.custom.template, that.custom.options),
                    null, 4
                )

                that.readyState = MockXMLHttpRequest.DONE
                that.dispatchEvent(new Event('readystatechange' /*, false, false, that*/ ))
                that.dispatchEvent(new Event('load' /*, false, false, that*/ ));
                that.dispatchEvent(new Event('loadend' /*, false, false, that*/ ));
            }

可以发现是定时或者非定时然后执行done，done内部执行convert执行到我们的函数

    // 数据模板 ＝> 响应数据
    function convert(item, options) {
        return Util.isFunction(item.template) ?
            item.template(options) : MockXMLHttpRequest.Mock.mock(item.template)
    }

然而不支持async函数，很麻烦...只是同步的伪造数据还好
如果根据提交参数做异步的获取并且再返回就会不兼容直接变成undefined
因为done解耦做的还挺好的，所以可以直接改done
首先把done改成async
判断结果是否是promise，如果是promise就阻塞一下再继续调用

然后我们可以改一下convert
因为async函数得到的是asyncfunction，而原来的是直接判断function是否是’function‘字符串
所以我们可以修改一下

目前测试是通的

修改的函数代码

            if (this.custom.async)
              setTimeout(() => {
                done();
              }, this.custom.timeout);
            // 异步
            else done(); // 同步
            async function done() {
              that.readyState = MockXMLHttpRequest.HEADERS_RECEIVED;
              that.dispatchEvent(
                new Event('readystatechange' /*, false, false, that*/)
              );
              that.readyState = MockXMLHttpRequest.LOADING;
              that.dispatchEvent(
                new Event('readystatechange' /*, false, false, that*/)
              );

              that.status = 200;
              that.statusText = HTTP_STATUS_CODES[200];
              const likePromise = convert(
                that.custom.template,
                that.custom.options
              );
              let result = likePromise;
              if (likePromise.then !== undefined) {
                result = await likePromise;
              }
              // fix #92 #93 by @qddegtya
              that.response = that.responseText = JSON.stringify(
                result,
                null,
                4
              );

              that.readyState = MockXMLHttpRequest.DONE;
              that.dispatchEvent(
                new Event('readystatechange' /*, false, false, that*/)
              );
              that.dispatchEvent(new Event('load' /*, false, false, that*/));
              that.dispatchEvent(new Event('loadend' /*, false, false, that*/));
            }

修改convert函数

        // 数据模板 ＝> 响应数据
        function convert(item, options) {
          return Util.type(item.template) === 'function' ||
            Util.type(item.template) === 'asyncfunction'
            ? item.template(options)
            : MockXMLHttpRequest.Mock.mock(item.template);
        }