Node.js 使用https，我如何针对未定义的状态代码设置条件？_Node.js_Https_Undefined

Node.js 使用https，我如何针对未定义的状态代码设置条件？

node.js https

Node.js 使用https，我如何针对未定义的状态代码设置条件？,node.js,https,undefined,Node.js,Https,Undefined,试图在模块中测试HTTP状态代码，但我的第一个响应总是undefined： foo.js const pass = require('./bar'); (async function() { const test = await pass('https://www.google.com/'); // URL for testing will be API URL console.log(`The return is: ${test}`); })(); const pass

试图在模块中测试HTTP状态代码，但我的第一个响应总是

undefined

：

foo.js

const pass = require('./bar');

(async function() {
    const test = await pass('https://www.google.com/'); // URL for testing will be API URL

    console.log(`The return is: ${test}`);
})();

const pass = require('./bar');

pass('https://www.google.com/', test => {
    console.log(`The return is: ${test}`);
});

bar.js

const https = require('https');

module.exports = (url) => {
    return new Promise((resolve, reject) => {
        https
        .get(url, (res) => {
            console.log(res.statusCode)
            if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
                console.log(`Results: ${res.statusCode}`)
                resolve(true)
            } else {
                resolve(false)
            }
        })
        .on('error', (e) => {
            console.error(`Error ${e}`)
            resolve(false)
        })
    });
}

const https = require('https');

module.exports = (url, callback) => {
    https
    .get(url, (res) => {
        console.log(res.statusCode)
        if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
            console.log(`Results: ${res.statusCode}`)
            callback(true)
        } else {
            callback(false)
        }
    })
    .on('error', (e) => {
        console.error(`Error ${e}`)
        callback(false)
    })
}

尝试1:

module.exports = (url) => {
  https
    .get(url, (res) => {
      console.log(res.statusCode)
      if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
       console.log(`Results: ${res.statusCode}`)
       return true
      }
      function waiting(status) {
        if (typeof status !== 'undefined') {
          console.log('run timeout')
          setTimeout(waiting, 250)
        } else {
          console.log(`Results: ${status}`)
          return true
        }
      }
    })
    .on('error', (e) => {
      console.error(`Error ${e}`)
      return false
    })
}

module.exports = (url) => {
  https
    .get(url, (res) => {
      console.log(res.statusCode)
      function waiting(status) {
        if (typeof status !== 'undefined') {
          console.log('run timeout')
          setTimeout(waiting, 250)
        } else {
          console.log(`Results: ${status}`)
          return true
        }
      }
    })
    .on('error', (e) => {
      console.error(`Error ${e}`)
      return false
    })
}

if (typeof res.statusCode === 'number' && res.statusCode !== undefined && res.statusCode !== null) {

if (!res.statusCode) {

if (typeof res.statusCode !== 'undefined') {
  console.log(`Results: ${res.statusCode}`)
  if (res.statusCode.toString()[0] === '2') return true
  return false
}

尝试2:

module.exports = (url) => {
  https
    .get(url, (res) => {
      console.log(res.statusCode)
      if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
       console.log(`Results: ${res.statusCode}`)
       return true
      }
      function waiting(status) {
        if (typeof status !== 'undefined') {
          console.log('run timeout')
          setTimeout(waiting, 250)
        } else {
          console.log(`Results: ${status}`)
          return true
        }
      }
    })
    .on('error', (e) => {
      console.error(`Error ${e}`)
      return false
    })
}

module.exports = (url) => {
  https
    .get(url, (res) => {
      console.log(res.statusCode)
      function waiting(status) {
        if (typeof status !== 'undefined') {
          console.log('run timeout')
          setTimeout(waiting, 250)
        } else {
          console.log(`Results: ${status}`)
          return true
        }
      }
    })
    .on('error', (e) => {
      console.error(`Error ${e}`)
      return false
    })
}

if (typeof res.statusCode === 'number' && res.statusCode !== undefined && res.statusCode !== null) {

if (!res.statusCode) {

if (typeof res.statusCode !== 'undefined') {
  console.log(`Results: ${res.statusCode}`)
  if (res.statusCode.toString()[0] === '2') return true
  return false
}

检测未定义的

的其他尝试：

module.exports = (url) => {
  https
    .get(url, (res) => {
      console.log(res.statusCode)
      if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
       console.log(`Results: ${res.statusCode}`)
       return true
      }
      function waiting(status) {
        if (typeof status !== 'undefined') {
          console.log('run timeout')
          setTimeout(waiting, 250)
        } else {
          console.log(`Results: ${status}`)
          return true
        }
      }
    })
    .on('error', (e) => {
      console.error(`Error ${e}`)
      return false
    })
}

module.exports = (url) => {
  https
    .get(url, (res) => {
      console.log(res.statusCode)
      function waiting(status) {
        if (typeof status !== 'undefined') {
          console.log('run timeout')
          setTimeout(waiting, 250)
        } else {
          console.log(`Results: ${status}`)
          return true
        }
      }
    })
    .on('error', (e) => {
      console.error(`Error ${e}`)
      return false
    })
}

if (typeof res.statusCode === 'number' && res.statusCode !== undefined && res.statusCode !== null) {

if (!res.statusCode) {

if (typeof res.statusCode !== 'undefined') {
  console.log(`Results: ${res.statusCode}`)
  if (res.statusCode.toString()[0] === '2') return true
  return false
}

研究：
module.exports = (url) => {
  https
    .get(url, (res) => {
      console.log(res.statusCode)
      if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
       console.log(`Results: ${res.statusCode}`)
       return true
      }
      function waiting(status) {
        if (typeof status !== 'undefined') {
          console.log('run timeout')
          setTimeout(waiting, 250)
        } else {
          console.log(`Results: ${status}`)
          return true
        }
      }
    })
    .on('error', (e) => {
      console.error(`Error ${e}`)
      return false
    })
}

module.exports = (url) => {
  https
    .get(url, (res) => {
      console.log(res.statusCode)
      function waiting(status) {
        if (typeof status !== 'undefined') {
          console.log('run timeout')
          setTimeout(waiting, 250)
        } else {
          console.log(`Results: ${status}`)
          return true
        }
      }
    })
    .on('error', (e) => {
      console.error(`Error ${e}`)
      return false
    })
}

if (typeof res.statusCode === 'number' && res.statusCode !== undefined && res.statusCode !== null) {

if (!res.statusCode) {

if (typeof res.statusCode !== 'undefined') {
  console.log(`Results: ${res.statusCode}`)
  if (res.statusCode.toString()[0] === '2') return true
  return false
}






我做错了什么？在我的模块中，如何检查未定义
后的状态代码，以便从实际数值返回真
或假
 在两次尝试中，bar.js中导出的函数都没有返回任何内容。由于您正在调用一个异步函数（https.get
），因此您需要导出的函数也是异步的。您可以在调用端使用承诺和异步/等待转换函数。例如
foo.js
const pass = require('./bar');

(async function() {
    const test = await pass('https://www.google.com/'); // URL for testing will be API URL

    console.log(`The return is: ${test}`);
})();


const pass = require('./bar');

pass('https://www.google.com/', test => {
    console.log(`The return is: ${test}`);
}); 

请注意IFEE以获得异步作用域，如下所示：
bar.js
const https = require('https');

module.exports = (url) => {
    return new Promise((resolve, reject) => {
        https
        .get(url, (res) => {
            console.log(res.statusCode)
            if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
                console.log(`Results: ${res.statusCode}`)
                resolve(true)
            } else {
                resolve(false)
            }
        })
        .on('error', (e) => {
            console.error(`Error ${e}`)
            resolve(false)
        })
    });
}


const https = require('https');

module.exports = (url, callback) => {
    https
    .get(url, (res) => {
        console.log(res.statusCode)
        if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
            console.log(`Results: ${res.statusCode}`)
            callback(true)
        } else {
            callback(false)
        }
    })
    .on('error', (e) => {
        console.error(`Error ${e}`)
        callback(false)
    })
}

或者，您可以按如下方式使用回调：
foo.js
const pass = require('./bar');

(async function() {
    const test = await pass('https://www.google.com/'); // URL for testing will be API URL

    console.log(`The return is: ${test}`);
})();


const pass = require('./bar');

pass('https://www.google.com/', test => {
    console.log(`The return is: ${test}`);
}); 

bar.js
const https = require('https');

module.exports = (url) => {
    return new Promise((resolve, reject) => {
        https
        .get(url, (res) => {
            console.log(res.statusCode)
            if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
                console.log(`Results: ${res.statusCode}`)
                resolve(true)
            } else {
                resolve(false)
            }
        })
        .on('error', (e) => {
            console.error(`Error ${e}`)
            resolve(false)
        })
    });
}


const https = require('https');

module.exports = (url, callback) => {
    https
    .get(url, (res) => {
        console.log(res.statusCode)
        if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
            console.log(`Results: ${res.statusCode}`)
            callback(true)
        } else {
            callback(false)
        }
    })
    .on('error', (e) => {
        console.error(`Error ${e}`)
        callback(false)
    })
}

在两次尝试中，bar.js中导出的函数都没有返回任何内容。由于您正在调用一个异步函数（https.get
），因此您需要导出的函数也是异步的。您可以在调用端使用承诺和异步/等待转换函数。例如
foo.js
const pass = require('./bar');

(async function() {
    const test = await pass('https://www.google.com/'); // URL for testing will be API URL

    console.log(`The return is: ${test}`);
})();


const pass = require('./bar');

pass('https://www.google.com/', test => {
    console.log(`The return is: ${test}`);
}); 

请注意IFEE以获得异步作用域，如下所示：
bar.js
const https = require('https');

module.exports = (url) => {
    return new Promise((resolve, reject) => {
        https
        .get(url, (res) => {
            console.log(res.statusCode)
            if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
                console.log(`Results: ${res.statusCode}`)
                resolve(true)
            } else {
                resolve(false)
            }
        })
        .on('error', (e) => {
            console.error(`Error ${e}`)
            resolve(false)
        })
    });
}


const https = require('https');

module.exports = (url, callback) => {
    https
    .get(url, (res) => {
        console.log(res.statusCode)
        if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
            console.log(`Results: ${res.statusCode}`)
            callback(true)
        } else {
            callback(false)
        }
    })
    .on('error', (e) => {
        console.error(`Error ${e}`)
        callback(false)
    })
}

或者，您可以按如下方式使用回调：
foo.js
const pass = require('./bar');

(async function() {
    const test = await pass('https://www.google.com/'); // URL for testing will be API URL

    console.log(`The return is: ${test}`);
})();


const pass = require('./bar');

pass('https://www.google.com/', test => {
    console.log(`The return is: ${test}`);
}); 

bar.js
const https = require('https');

module.exports = (url) => {
    return new Promise((resolve, reject) => {
        https
        .get(url, (res) => {
            console.log(res.statusCode)
            if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
                console.log(`Results: ${res.statusCode}`)
                resolve(true)
            } else {
                resolve(false)
            }
        })
        .on('error', (e) => {
            console.error(`Error ${e}`)
            resolve(false)
        })
    });
}


const https = require('https');

module.exports = (url, callback) => {
    https
    .get(url, (res) => {
        console.log(res.statusCode)
        if (typeof res.statusCode !== 'undefined' && res.statusCode.toString()[0] === '2') {
            console.log(`Results: ${res.statusCode}`)
            callback(true)
        } else {
            callback(false)
        }
    })
    .on('error', (e) => {
        console.error(`Error ${e}`)
        callback(false)
    })
}

如果有人想使用异步函数方法，请注意，有些人会要求将其编写为；（async function（）{//code}）（
。如果有人想使用async function方法，请注意，有些人会要求将其编写为；（异步函数（）{//code}）（
）。