如何避免代码重复在JavaScript中附加的片段

How to avoid code duplication in JavaScript in the attached snippet?

本文关键字：片段 JavaScript 何避免 代码      更新时间：2023-09-26

我试图使用Open Weather地图找到天气，我有2种方法，findWeatherByLocation和findWeatherByCity。我假设JavaScript不支持method overloading，因此有两个不同的名称。这两个方法都接受一个callback函数，该函数将被触发并执行相同的操作。

function findWeatherForCity(senderID, city, countryCode, callback) {
    //Lets configure and request
    request({
        url: constants.OPEN_WEATHER_MAP_BASE_URL, //URL to hit
        qs: {
            q: city + ',' + countryCode,
            appid: constants.OPEN_WEATHER_MAP_API_KEY
        }, //Query string data
        method: 'GET', //Specify the method
    }, function (error, response, body) {
        if (!error && response.statusCode == 200) {
            let weather = getWeatherReport(JSON.parse(body));
            callback(weather ? weather : null);
        }
        else {
            console.error(response.error);
            callback(null);
        }
    });
}
/*
 lat, lon coordinates of the location of your interest   
 * http://openweathermap.org/current
 */
function findWeatherForLocation(senderID, location, callback) {
    //Lets configure and request
    request({
        url: constants.OPEN_WEATHER_MAP_BASE_URL, //URL to hit
        qs: {
            lat: location.lat,
            lon: location.lon,
            appid: constants.OPEN_WEATHER_MAP_API_KEY
        }, //Query string data
        method: 'GET', //Specify the method
    }, function (error, response, body) {
        if (!error && response.statusCode == 200) {
            let report = getWeatherReport(JSON.parse(body));
            callback(report ? report : null);
        }
        else {
            console.error(response.error)
            callback(null);
        }
    });
}

可以看到，function(error, response, body)在两个地方做同样的事情。如果我为findWeatherByCity和findWeatherByLocation创建一个单独的function(error, response, body)，我如何触发callback ?

提前感谢您的帮助

我已经使用承诺来重构回调并整理代码，但是你可以用回调来代替它们，尽管我不建议这样做(已经是2016年了)。

/* you are not using senderID anywhere but i left it cuz you had it.*/
function findWeather(senderID, queryType, options) {
  return new Promise(function(resolve, reject) {
    var queryObj = {
      appid: constants.OPEN_WEATHER_MAP_API_KEY
    };
    if (queryType === 'city') {
      queryObj.q = options.city + ',' + options.countryCode;
    } else if (queryType === 'location') {
      queryObj.lat= options.lat;
      queryObj.lon= options.lon;
      }
    } else {
      reject('no valid queryType');
    }
    request({
      url: constants.OPEN_WEATHER_MAP_BASE_URL,
      qs: queryObj,
      method: 'GET'
    }, function(err, response, body) {
      if (!error && response.statusCode == 200) {
        let report = getWeatherReport(JSON.parse(body));
        resolve(report ? report : null);
      } else {
        reject(response.error);
      }
    });
  });
}
/*USAGE*/
findWeather(1, 'city', {
    city: 'Ramallah',
    countryCode: '00970'
  })
  .then(function(data) {
    console.log(data);
  });
findWeather(1, 'location', {
    lat: 1,
    lon: 2
  })
  .then(function(data) {
    console.log(data);
  })
  .catch(function(err) {
    console.log(err);
  });

这个问题不属于StackOverflow但是你可以这样做:

function responseHandler (error, response, body, callback) {
    if (!error && response.statusCode == 200) {
        let weather = getWeatherReport(JSON.parse(body));
        callback(weather ? weather : null);
    }
    else {
        console.error(response.error);
        callback(null);
    }
}
function findWeatherForCity(senderID, city, countryCode, callback) {
    //Lets configure and request
    request({
        url: constants.OPEN_WEATHER_MAP_BASE_URL, //URL to hit
        qs: {
            q: city + ',' + countryCode,
            appid: constants.OPEN_WEATHER_MAP_API_KEY
        }, //Query string data
        method: 'GET', //Specify the method
    }, function(error, response, body) {
        responseHandler(error, response, body, callback)
    });
}
/*
 lat, lon coordinates of the location of your interest
 * http://openweathermap.org/current
 */
function findWeatherForLocation(senderID, location, callback) {
    //Lets configure and request
    request({
        url: constants.OPEN_WEATHER_MAP_BASE_URL, //URL to hit
        qs: {
            lat: location.lat,
            lon: location.lon,
            appid: constants.OPEN_WEATHER_MAP_API_KEY
        }, //Query string data
        method: 'GET', //Specify the method
    }, function(error, response, body) {
        responseHandler(error, response, body, callback)
    });
}
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