NodeJS-Promise-Callback

热度 ℃

在 JavaScript 中编写同时支持 Promise 和 Callback 语法的函数调用；

同时支持 Promise 调用也支持 Callback 异步回调的函数，假定其调用方式规定如下：

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var client = new CNodeJS({
	url: 'http://127.0.0.1:3000/hw/',
});
// 
client.request(params)
	.then(function(data){
	})
	.catch(function(err){
	});
//
client.request(params, function callback(err, data){
});

函数定义

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'use strict';
var request = require('request');
class CNodeJS {
	constructor(options) {
		this.options = options||{};
		options.url = options.url || "http://127.0.0.1:3000/hw/";
	}
	baseParams(params) {
		params = Object.assign({}, params || {});
		if(this.options.token){
			params.accesstoken = this.options.token;
		}
		return params;
	}
	request1(method, path, params) {
		return new Promise((resolve, reject) => {
			var opts = {
				method : method.toUpperCase(),
				url : this.options.url + path,
				json : true,
			};
			if(opts.method === 'GET' || opts.method === 'HEAD') {
				opts.qs = this.baseParams(params);
			}else{
				opts.body = this.baseParams(params);
			}
			request(opts, (err, res, body) => {
				if(err){
					return reject(err);
				}
				if(body){
					// body || res.body
					resolve(body);
				}else{
					reject(new Error("body#error"));
				}
			});
		});
	}
	request2(method, path, params, callback) {
		return new Promise((resolve_, reject_) => {
			var opts = {
				method : method.toUpperCase(),
				url : this.options.url + path,
				json : true,
			};
			if(opts.method === 'GET' || opts.method === 'HEAD') {
				opts.qs = this.baseParams(params);
			}else{
				opts.body = this.baseParams(params);
			}
			const resolve = res => {
				resolve_(res);
				callback && callback(null, res);
			};
			const reject = err => {
				reject_(err);
				callback && callback(err);
			}
			request(opts, (err, res, body) => {
				if(err){
					return reject(err);
				}
				if(body){
					// body || res.body
					resolve(body);
				}else{
					reject(new Error("body#error"));
				}
			});
		});
	}
	request3(method, path, params, callback) {
		return request2(method, path, params, callback)
			.then(result => Promise.resolve(result.data));
	}
}
var client = new CNodeJS({
	url: 'http://127.0.0.1:3000/hw/',
});
// 仅支持 Promise
client.request1('GET', 'abc', {})
	.then(result => console.log(result))
	.catch(err => console.error(err));
// 支持 Promise 和 Callback
client.request2('GET', 'abc', {}, function callback(err, res) {
	// body...
	if(err){
		console.error(err);
	}else{
		console.log("callback:");
		console.log(res);
	}
});
// 请求3 => 转换服务器返回的数据
client.request3('GET', 'dbc', {})
	.then(result => console.log(result))
	.catch(err => console.log(err));

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