伍:axios1.x改动内容

前边我们对axios0.18.0的源码内容做了解读，但是0.18.0的版本有些老了，从github拉了axios1.0.0-beta版本来看一下有了哪些变动吧

目录结构与入口文件

目录结构与旧版本基本一致，只有些许变动。

lib	// 源码目录
|---- adapters	// 适配器目录
| |---- index.js  // ++++++++++++++++++++++++
|	|---- xhr.js  // 浏览器xhr
|	|---- http.js  // node环境http|
|---- cancel  // 取消请求相关功能目录
|	|---- CanceledError.js // ++++++++++++++++++
|	|---- CancelToken.js
|	|---- isCancel.js
|---- core	// 核心代码目录
|	|---- Axios.js	// Axios类，用于创建axios实例
|	|---- dispatchRequest.js  // 封装发送请求的方法
|	|---- InterceptorManager.js	// 拦截器
|	|---- settle.js
|	|---- transformData.js	// 数据转换
|---- helpers	// 一些辅助函数
|---- defaults // 默认配置 修改为目录
|---- axios.js	// 真正的入口文件
|---- utils.js	// 一些公共方法

代码有了些或多或少的改动，位置也有了一些变化，语法也用上了ES6，但是内部的思想还是没有什么大的改动的。

axios.js

lib/axios.js加了几个新方法，但是更大的改动我觉得是createInstance这个方法。

function createInstance(defaultConfig) {
  const context = new Axios(defaultConfig);
  const instance = bind(Axios.prototype.request, context);

  // Copy axios.prototype to instance
  utils.extend(instance, Axios.prototype, context, {allOwnKeys: true});

  // Copy context to instance
  utils.extend(instance, context, {allOwnKeys: true});

  // Factory for creating new instances
  instance.create = function create(instanceConfig) {
    return createInstance(mergeConfig(defaultConfig, instanceConfig));
  };

  return instance;
}

现在create方法是在craeteInstance方法添加到实例上的了，这也就意味着通过axios.creaet()创建的实例依然可以调用create方法，这是与老版本不同的。

axios还添加了一个有意思的方法formToJSON()，但是通过axios.create创建的实例依然不能调用CancelToken等用于取消请求的方法。

CancelToken

CancelToken的改动也挺大的，改用了listeners去收集需要取消的请求。

'use strict';

import CanceledError from './CanceledError.js';

/**
 * A `CancelToken` is an object that can be used to request cancellation of an operation.
 *
 * @param {Function} executor The executor function.
 *
 * @returns {CancelToken}
 */
class CancelToken {
  constructor(executor) {
    if (typeof executor !== 'function') {
      throw new TypeError('executor must be a function.');
    }

    let resolvePromise;

    this.promise = new Promise(function promiseExecutor(resolve) {
      resolvePromise = resolve;
    });

    const token = this;

    // eslint-disable-next-line func-names
    this.promise.then(cancel => {
      if (!token._listeners) return;

      let i = token._listeners.length;

      while (i-- > 0) {
        token._listeners[i](cancel);
      }
      token._listeners = null;
    });

    // eslint-disable-next-line func-names
    this.promise.then = onfulfilled => {
      let _resolve;
      // eslint-disable-next-line func-names
      const promise = new Promise(resolve => {
        token.subscribe(resolve);
        _resolve = resolve;
      }).then(onfulfilled);

      promise.cancel = function reject() {
        token.unsubscribe(_resolve);
      };

      return promise;
    };

    executor(function cancel(message, config, request) {
      if (token.reason) {
        // Cancellation has already been requested
        return;
      }

      token.reason = new CanceledError(message, config, request);
      resolvePromise(token.reason);
    });
  }

  /**
   * Throws a `CanceledError` if cancellation has been requested.
   */
  throwIfRequested() {
    if (this.reason) {
      throw this.reason;
    }
  }

  /**
   * Subscribe to the cancel signal
   */

  subscribe(listener) {
    if (this.reason) {
      listener(this.reason);
      return;
    }

    if (this._listeners) {
      this._listeners.push(listener);
    } else {
      this._listeners = [listener];
    }
  }

  /**
   * Unsubscribe from the cancel signal
   */

  unsubscribe(listener) {
    if (!this._listeners) {
      return;
    }
    const index = this._listeners.indexOf(listener);
    if (index !== -1) {
      this._listeners.splice(index, 1);
    }
  }

  /**
   * Returns an object that contains a new `CancelToken` and a function that, when called,
   * cancels the `CancelToken`.
   */
  static source() {
    let cancel;
    const token = new CancelToken(function executor(c) {
      cancel = c;
    });
    return {
      token,
      cancel
    };
  }
}

export default CancelToken;

xhr

dispatchRequest基本是没有改动的，但是xhr适配器还是有一些改动的，取消请求的部分也随着CancelToken的变动有了不小的变动。

function progressEventReducer(listener, isDownloadStream) {
  let bytesNotified = 0;
  const _speedometer = speedometer(50, 250);

  return e => {
    const loaded = e.loaded;
    const total = e.lengthComputable ? e.total : undefined;
    const progressBytes = loaded - bytesNotified;
    const rate = _speedometer(progressBytes);
    const inRange = loaded <= total;

    bytesNotified = loaded;

    const data = {
      loaded,
      total,
      progress: total ? (loaded / total) : undefined,
      bytes: progressBytes,
      rate: rate ? rate : undefined,
      estimated: rate && total && inRange ? (total - loaded) / rate : undefined
    };

    data[isDownloadStream ? 'download' : 'upload'] = true;

    listener(data);
  };
}

export default function xhrAdapter(config) {
  return new Promise(function dispatchXhrRequest(resolve, reject) {
    let requestData = config.data;
    const requestHeaders = AxiosHeaders.from(config.headers).normalize();
    const responseType = config.responseType;
    let onCanceled;
    function done() {
      if (config.cancelToken) {
        config.cancelToken.unsubscribe(onCanceled);
      }

      if (config.signal) {
        config.signal.removeEventListener('abort', onCanceled);
      }
    }

    if (utils.isFormData(requestData) && utils.isStandardBrowserEnv()) {
      requestHeaders.setContentType(false); // Let the browser set it
    }

    let request = new XMLHttpRequest();

    // HTTP basic authentication
    if (config.auth) {
      const username = config.auth.username || '';
      const password = config.auth.password ? unescape(encodeURIComponent(config.auth.password)) : '';
      requestHeaders.set('Authorization', 'Basic ' + btoa(username + ':' + password));
    }

    const fullPath = buildFullPath(config.baseURL, config.url);

    request.open(config.method.toUpperCase(), buildURL(fullPath, config.params, config.paramsSerializer), true);

    // Set the request timeout in MS
    request.timeout = config.timeout;

    function onloadend() {
      if (!request) {
        return;
      }
      // Prepare the response
      const responseHeaders = AxiosHeaders.from(
        'getAllResponseHeaders' in request && request.getAllResponseHeaders()
      );
      const responseData = !responseType || responseType === 'text' ||  responseType === 'json' ?
        request.responseText : request.response;
      const response = {
        data: responseData,
        status: request.status,
        statusText: request.statusText,
        headers: responseHeaders,
        config,
        request
      };

      settle(function _resolve(value) {
        resolve(value);
        done();
      }, function _reject(err) {
        reject(err);
        done();
      }, response);

      // Clean up request
      request = null;
    }

    if ('onloadend' in request) {
      // Use onloadend if available
      request.onloadend = onloadend;
    } else {
      // Listen for ready state to emulate onloadend
      request.onreadystatechange = function handleLoad() {
        if (!request || request.readyState !== 4) {
          return;
        }

        // The request errored out and we didn't get a response, this will be
        // handled by onerror instead
        // With one exception: request that using file: protocol, most browsers
        // will return status as 0 even though it's a successful request
        if (request.status === 0 && !(request.responseURL && request.responseURL.indexOf('file:') === 0)) {
          return;
        }
        // readystate handler is calling before onerror or ontimeout handlers,
        // so we should call onloadend on the next 'tick'
        setTimeout(onloadend);
      };
    }

    // Handle browser request cancellation (as opposed to a manual cancellation)
    request.onabort = function handleAbort() {
      if (!request) {
        return;
      }

      reject(new AxiosError('Request aborted', AxiosError.ECONNABORTED, config, request));

      // Clean up request
      request = null;
    };

    // Handle low level network errors
    request.onerror = function handleError() {
      // Real errors are hidden from us by the browser
      // onerror should only fire if it's a network error
      reject(new AxiosError('Network Error', AxiosError.ERR_NETWORK, config, request));

      // Clean up request
      request = null;
    };

    // Handle timeout
    request.ontimeout = function handleTimeout() {
      let timeoutErrorMessage = config.timeout ? 'timeout of ' + config.timeout + 'ms exceeded' : 'timeout exceeded';
      const transitional = config.transitional || transitionalDefaults;
      if (config.timeoutErrorMessage) {
        timeoutErrorMessage = config.timeoutErrorMessage;
      }
      reject(new AxiosError(
        timeoutErrorMessage,
        transitional.clarifyTimeoutError ? AxiosError.ETIMEDOUT : AxiosError.ECONNABORTED,
        config,
        request));

      // Clean up request
      request = null;
    };

    // Add xsrf header
    // This is only done if running in a standard browser environment.
    // Specifically not if we're in a web worker, or react-native.
    if (utils.isStandardBrowserEnv()) {
      // Add xsrf header
      const xsrfValue = (config.withCredentials || isURLSameOrigin(fullPath))
        && config.xsrfCookieName && cookies.read(config.xsrfCookieName);

      if (xsrfValue) {
        requestHeaders.set(config.xsrfHeaderName, xsrfValue);
      }
    }

    // Remove Content-Type if data is undefined
    requestData === undefined && requestHeaders.setContentType(null);

    // Add headers to the request
    if ('setRequestHeader' in request) {
      utils.forEach(requestHeaders.toJSON(), function setRequestHeader(val, key) {
        request.setRequestHeader(key, val);
      });
    }

    // Add withCredentials to request if needed
    if (!utils.isUndefined(config.withCredentials)) {
      request.withCredentials = !!config.withCredentials;
    }

    // Add responseType to request if needed
    if (responseType && responseType !== 'json') {
      request.responseType = config.responseType;
    }

    // Handle progress if needed
    if (typeof config.onDownloadProgress === 'function') {
      request.addEventListener('progress', progressEventReducer(config.onDownloadProgress, true));
    }

    // Not all browsers support upload events
    if (typeof config.onUploadProgress === 'function' && request.upload) {
      request.upload.addEventListener('progress', progressEventReducer(config.onUploadProgress));
    }

    if (config.cancelToken || config.signal) {
      // Handle cancellation
      // eslint-disable-next-line func-names
      onCanceled = cancel => {
        if (!request) {
          return;
        }
        reject(!cancel || cancel.type ? new CanceledError(null, config, request) : cancel);
        request.abort();
        request = null;
      };

      config.cancelToken && config.cancelToken.subscribe(onCanceled);
      if (config.signal) {
        config.signal.aborted ? onCanceled() : config.signal.addEventListener('abort', onCanceled);
      }
    }

    // false, 0 (zero number), and '' (empty string) are valid JSON values
    if (!requestData && requestData !== false && requestData !== 0 && requestData !== '') {
      requestData = null;
    }

    const protocol = parseProtocol(fullPath);

    if (protocol && platform.protocols.indexOf(protocol) === -1) {
      reject(new AxiosError('Unsupported protocol ' + protocol + ':', AxiosError.ERR_BAD_REQUEST, config));
      return;
    }


    // Send the request
    request.send(requestData);
  });
}

本篇主要是把一些大的变动的内容给列出来了，没有对axios1.x对源码做解读。

至于会不会有axios1.x对源码解读还是看后续的时间吧