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/