我试图跟踪在同一个键中出现四个特定字符串值的次数。

问题是,我很难添加多个计数器。第一个计数器起作用并跟踪第一个条件,但是if / else语句中的下一个条件会阻止初始条件和此后的每个条件正确加总。数据来自包含多个URL的Promise.all

这是我的代码:

const urls = [
  'https://api.github.com/users/TylerP33/repos?page=1',
  'https://api.github.com/users/TylerP33/repos?page=2',
  'https://api.github.com/users/TylerP33/repos?page=3',
  'https://api.github.com/users/TylerP33/repos?page=4',
  'https://api.github.com/users/TylerP33/repos?page=5',
  'https://api.github.com/users/TylerP33/repos?page=6',
  'https://api.github.com/users/TylerP33/repos?page=7',
  'https://api.github.com/users/TylerP33/repos?page=8',
  'https://api.github.com/users/TylerP33/repos?page=9',
  'https://api.github.com/users/TylerP33/repos?page=10',
  'https://api.github.com/users/TylerP33/repos?page=11',
  'https://api.github.com/users/TylerP33/repos?page=12'
]


function getLanguages() {
  return Promise.all(urls.map(url =>
    fetch(`${url}`)
    .then(response => response.json())
    .then(obj => obj.forEach(function(val) {
      var rubyCounter = 0
      var cssCounter = 0
      var htmlCounter = 0
      var jsCounter = 0
      if (val.language === "Ruby") {
        rubyCounter++;
        console.log(rubyCounter);
      }

    })))
  )
}

getLanguages();


rubyCounter将返回235,这是正确的数量,但是如果我再添加一些条件,就像通过同一键运行的true / false条件会抛出所有错误。我可能想念一些明显的东西,但是我很好奇看到你们的想法。

提前致谢。

最佳答案

对于此代码,如果rubyCounter记录下来,它将始终为1,因为这些计数器始终在回调中初始化。

您需要将这些计数器的定义移到getLanguages的根。

而且,我不是使用每个计数器的多元变量,而是使用一个对象,并且对于要计数的每种语言都使用一个属性。



const urls = [
  'https://api.github.com/users/TylerP33/repos?page=1',
  'https://api.github.com/users/TylerP33/repos?page=2',
  'https://api.github.com/users/TylerP33/repos?page=3',
  'https://api.github.com/users/TylerP33/repos?page=4',
  'https://api.github.com/users/TylerP33/repos?page=5',
  'https://api.github.com/users/TylerP33/repos?page=6',
  'https://api.github.com/users/TylerP33/repos?page=7',
  'https://api.github.com/users/TylerP33/repos?page=8',
  'https://api.github.com/users/TylerP33/repos?page=9',
  'https://api.github.com/users/TylerP33/repos?page=10',
  'https://api.github.com/users/TylerP33/repos?page=11',
  'https://api.github.com/users/TylerP33/repos?page=12'
]


function getLanguages() {
  let counter = {
    ruby: 0,
    html: 0
  }

  return Promise.all(urls.map(url =>
      fetch(`${url}`)
      .then(response => response.json())
      .then(obj => obj.forEach(function(val) {
        /*var rubyCounter = 0
        var cssCounter = 0
        var htmlCounter = 0
        var jsCounter = 0*/
        if (val.language === "Ruby") {
          counter.ruby++;
        } else if (val.language === "HTML") {
          counter.html++;
        }

      }))))
    .then(() => {
      console.dir(counter)
    })
}

getLanguages();





如果您想说所有语言,那就更简单了:



const urls = [
  'https://api.github.com/users/TylerP33/repos?page=1',
  'https://api.github.com/users/TylerP33/repos?page=2',
  'https://api.github.com/users/TylerP33/repos?page=3',
  'https://api.github.com/users/TylerP33/repos?page=4',
  'https://api.github.com/users/TylerP33/repos?page=5',
  'https://api.github.com/users/TylerP33/repos?page=6',
  'https://api.github.com/users/TylerP33/repos?page=7',
  'https://api.github.com/users/TylerP33/repos?page=8',
  'https://api.github.com/users/TylerP33/repos?page=9',
  'https://api.github.com/users/TylerP33/repos?page=10',
  'https://api.github.com/users/TylerP33/repos?page=11',
  'https://api.github.com/users/TylerP33/repos?page=12'
]


function getLanguages() {
  let counter = {}

  return Promise.all(urls.map(url =>
      fetch(`${url}`)
      .then(response => response.json())
      .then(obj => obj.forEach(function(val) {
        if( val.language ) {
          counter[val.language] = counter[val.language] || 0
          counter[val.language]++
        }
      }))))
    .then(() => {
      console.dir(counter)
    })
}

getLanguages();

关于javascript - 计算对象中同一键内的多个唯一值,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/52024068/

10-12 12:51
查看更多