Javascript菜单递归函数错误
Javascript菜单递归函数错误
提问于 2017-05-19 10:09:28
//当前操纵http://jsfiddle.net/0ht35rpb/45/
我试图遍历一个json导航树，这样当一个人进入一个特定的页面时，它就会找到它的替代语言反部分。
//JSON
{
"langs" : [
{
"lang" : "de",
"lines" : {
"menu" : [
{
"title" : "Anleitung",
"link" : "/de/anleitung"
},
{
"title" : "Funktionen",
"link" : "/de/funktionen"
},
{
"title" : "Dienstleistungen",
"link" : "/de/dienstleistungen",
"children" : [
{
"title" : "Geistiges Eigentum",
"link" : "/de/dienstleistungen/geistiges-eigentum"
},
{
"title" : "Compliance",
"link" : "/de/dienstleistungen/compliance"
},
{
"title" : "Investment- und Beteiligungsrecht",
"link" : "/de/dienstleistungen/beteiligungsrecht"
},
{
"title" : "Mergers & Acquisitions",
"link" : "/de/dienstleistungen/mergers-and-acquisitions"
},
{
"title" : "Immobilienrecht",
"link" : "/de/dienstleistungen/immobilienrecht"
},
{
"title" : "Internet- und Datenschutzrecht",
"link" : "/de/dienstleistungen/internetrecht"
},
{
"title" : "Gesellschaftsrecht",
"link" : "/de/dienstleistungen/gesellschaftsrecht"
},
{
"title" : "Handelsrecht",
"link" : "/de/dienstleistungen/handelsrecht"
},
{
"title" : "Arbeitsrecht",
"link" : "/de/dienstleistungen/arbeitsrecht"
},
{
"title" : "Bankrecht",
"link" : "/de/dienstleistungen/bankrecht"
},
{
"title" : "Vertragsrecht",
"link" : "/de/dienstleistungen/vertragsrecht"
},
{
"title" : "Wettbewerbsrecht",
"link" : "/de/dienstleistungen/wettbewerbsrecht"
}
]
},
{
"title" : "Beliebte Projekte",
"link" : "/de/beliebte-projekte",
"children" : [
{
"title" : "Compliance",
"link" : "/de/beliebte-projekte/compliance",
"children" : [
{
"title" : "Haftungsrisiken für Geschäftsführern",
"link" : "/de/beliebte-projekte/compliance/haftungsrisken-geschaeftsfuehrern"
},
{
"title" : "Compliance-Prüfung KMU",
"link" : "/de/beliebte-projekte/compliance/compliance-pruefung-kmu"
}
]
}
]
}
],
"sign_in" : "Login"
}
},
{
"lang" : "en",
"lines" : {
"menu" : [
{
"title" : "How it works",
"link" : "/en/how-it-works"
},
{
"title" : "Features",
"link" : "/en/features"
},
{
"title" : "Services",
"link" : "/en/services",
"children" : [
{
"title" : "Intellectual property",
"link" : "/en/services/intellectual-property"
},
{
"title" : "Compliance",
"link" : "/en/services/compliance"
},
{
"title" : "Investment law",
"link" : "/en/services/investment-law"
},
{
"title" : "Mergers & Acquisitions",
"link" : "/en/services/mergers-and-acquisitions"
},
{
"title" : "Real estate law",
"link" : "/en/services/real-estate-law"
},
{
"title" : "Internet law and data privacy",
"link" : "/en/services/internet-law"
},
{
"title" : "Company law",
"link" : "/en/services/company-law"
},
{
"title" : "Trade law",
"link" : "/en/services/trade-law"
},
{
"title" : "Labour law",
"link" : "/en/services/labour-law"
},
{
"title" : "Bank law",
"link" : "/en/services/bank-law"
},
{
"title" : "Contract law",
"link" : "/en/services/contract-law"
},
{
"title" : "Competition law",
"link" : "/en/services/competition-law"
}
]
},
{
"title" : "Popular Projects",
"link" : "/en/popular-projects",
"children" : [
{
"title" : "Compliance",
"link" : "/en/popular-projects/compliance",
"children" : [
{
"title" : "Haf eng",
"link" : "/en/popular-projects/compliance/haf-eng"
},
{
"title" : "Compliance eng",
"link" : "/en/popular-projects/compliance/compliance-eng"
}
]
}
]
}
],
"sign_in" : "Sign in"
}
}
]
}我的js功能
所以在这种情况下
设想CURRENTLNG为en CURRENTURL as /en/services
在"/en/popular-projects/compliance/compliance-eng"，"/de/beliebte-projekte/compliance/compliance-pruefung-kmu“()中，我希望返回一个数组，其中包含"/en/services”、"/de/dienstleistungen“，这段代码在尝试获取第三级导航计数器部件fetchFooterUrls时失败了。
getUrl (pairUrl, currentLng, enMenu, deMenu, obj) {
for (let k in obj) {
if (!obj.hasOwnProperty(k)) continue
if (obj[k].link === pairUrl) {
if (currentLng === 'de') {
return enMenu[k].link // get en link equivlant
} else {
return deMenu[k].link // get de link equivlant
}
} else {
if (obj[k].hasOwnProperty('children') && obj[k].children.length > 0) continue
this.getUrl(pairUrl, currentLng, enMenu[k].children, deMenu[k].children, obj[k].children)
}
}
}
//
getLanguagePair (currentLng, pairUrl) {
// 'find url in json tree'
var enMenu = linkTreeObject.langs[1].lines.menu
var deMenu = linkTreeObject.langs[0].lines.menu
let obj = {}
// find position in tree
if (currentLng === 'de') {
obj = deMenu
} else {
obj = enMenu
}
return this.getUrl(pairUrl, currentLng, enMenu, deMenu, obj)
}
fetchFooterUrls () {
let deUrl = ''
let enUrl = ''
if (CURRENTLNG === 'de') {
deUrl = CURRENTURL
enUrl = this.getLanguagePair(CURRENTLNG, this.props.location.pathname)
} else {
enUrl = CURRENTURL
deUrl = this.getLanguagePair(CURRENTLNG, this.props.location.pathname)
}
return [enUrl, deUrl]
}//试图让这个片段-有主持人在这里解决吗？
var linkTreeObject ={
"langs" : [
{
"lang" : "de",
"lines" : {
"menu" : [
{
"title" : "Anleitung",
"link" : "/de/anleitung"
},
{
"title" : "Funktionen",
"link" : "/de/funktionen"
},
{
"title" : "Dienstleistungen",
"link" : "/de/dienstleistungen",
"children" : [
{
"title" : "Geistiges Eigentum",
"link" : "/de/dienstleistungen/geistiges-eigentum"
},
{
"title" : "Compliance",
"link" : "/de/dienstleistungen/compliance"
},
{
"title" : "Investment- und Beteiligungsrecht",
"link" : "/de/dienstleistungen/beteiligungsrecht"
},
{
"title" : "Mergers & Acquisitions",
"link" : "/de/dienstleistungen/mergers-and-acquisitions"
},
{
"title" : "Immobilienrecht",
"link" : "/de/dienstleistungen/immobilienrecht"
},
{
"title" : "Internet- und Datenschutzrecht",
"link" : "/de/dienstleistungen/internetrecht"
},
{
"title" : "Gesellschaftsrecht",
"link" : "/de/dienstleistungen/gesellschaftsrecht"
},
{
"title" : "Handelsrecht",
"link" : "/de/dienstleistungen/handelsrecht"
},
{
"title" : "Arbeitsrecht",
"link" : "/de/dienstleistungen/arbeitsrecht"
},
{
"title" : "Bankrecht",
"link" : "/de/dienstleistungen/bankrecht"
},
{
"title" : "Vertragsrecht",
"link" : "/de/dienstleistungen/vertragsrecht"
},
{
"title" : "Wettbewerbsrecht",
"link" : "/de/dienstleistungen/wettbewerbsrecht"
}
]
},
{
"title" : "Beliebte Projekte",
"link" : "/de/beliebte-projekte",
"children" : [
{
"title" : "Compliance",
"link" : "/de/beliebte-projekte/compliance",
"children" : [
{
"title" : "Haftungsrisiken für Geschäftsführern",
"link" : "/de/beliebte-projekte/compliance/haftungsrisken-geschaeftsfuehrern"
},
{
"title" : "Compliance-Prüfung KMU",
"link" : "/de/beliebte-projekte/compliance/compliance-pruefung-kmu"
}
]
}
]
}
],
"sign_in" : "Login"
}
},
{
"lang" : "en",
"lines" : {
"menu" : [
{
"title" : "How it works",
"link" : "/en/how-it-works"
},
{
"title" : "Features",
"link" : "/en/features"
},
{
"title" : "Services",
"link" : "/en/services",
"children" : [
{
"title" : "Intellectual property",
"link" : "/en/services/intellectual-property"
},
{
"title" : "Compliance",
"link" : "/en/services/compliance"
},
{
"title" : "Investment law",
"link" : "/en/services/investment-law"
},
{
"title" : "Mergers & Acquisitions",
"link" : "/en/services/mergers-and-acquisitions"
},
{
"title" : "Real estate law",
"link" : "/en/services/real-estate-law"
},
{
"title" : "Internet law and data privacy",
"link" : "/en/services/internet-law"
},
{
"title" : "Company law",
"link" : "/en/services/company-law"
},
{
"title" : "Trade law",
"link" : "/en/services/trade-law"
},
{
"title" : "Labour law",
"link" : "/en/services/labour-law"
},
{
"title" : "Bank law",
"link" : "/en/services/bank-law"
},
{
"title" : "Contract law",
"link" : "/en/services/contract-law"
},
{
"title" : "Competition law",
"link" : "/en/services/competition-law"
}
]
},
{
"title" : "Popular Projects",
"link" : "/en/popular-projects",
"children" : [
{
"title" : "Compliance",
"link" : "/en/popular-projects/compliance",
"children" : [
{
"title" : "Haf eng",
"link" : "/en/popular-projects/compliance/haf-eng"
},
{
"title" : "Compliance eng",
"link" : "/en/popular-projects/compliance/compliance-eng"
}
]
}
]
}
],
"sign_in" : "Sign in"
}
}
]
};
getUrl (pairUrl, currentLng, enMenu, deMenu, obj) {
for (let k in obj) {
if (!obj.hasOwnProperty(k)) continue
if (obj[k].link === pairUrl) {
if (currentLng === 'de') {
return enMenu[k].link // get en link equivlant
} else {
return deMenu[k].link // get de link equivlant
}
} else {
if (obj[k].hasOwnProperty('children') && obj[k].children.length > 0) continue
this.getUrl(pairUrl, currentLng, enMenu[k].children, deMenu[k].children, obj[k].children)
}
}
}
//
getLanguagePair (currentLng, pairUrl) {
// 'find url in json tree'
var enMenu = linkTreeObject.langs[1].lines.menu
var deMenu = linkTreeObject.langs[0].lines.menu
let obj = {}
// find position in tree
if (currentLng === 'de') {
obj = deMenu
} else {
obj = enMenu
}
return this.getUrl(pairUrl, currentLng, enMenu, deMenu, obj)
}
console.log(getLanguagePair("en", "/en/how-it-works"))回答 2
Stack Overflow用户
回答已采纳
发布于 2017-05-19 11:01:14
更新了弹琴。其他部分中与递归函数调用相关的错误。http://jsfiddle.net/gaganshera/0ht35rpb/51/
改到
if (!obj[k].hasOwnProperty('children') || obj[k].children.length <= 0) continue;
var ret = getUrl(pairUrl, currentLng, enMenu[k].children, deMenu[k].children, obj[k].children);
if(typeof ret != 'undefined') return ret;
var linkTreeObject = {
"langs": [{
"lang": "de",
"lines": {
"menu": [{
"title": "Anleitung",
"link": "/de/anleitung"
}, {
"title": "Funktionen",
"link": "/de/funktionen"
}, {
"title": "Dienstleistungen",
"link": "/de/dienstleistungen",
"children": [{
"title": "Geistiges Eigentum",
"link": "/de/dienstleistungen/geistiges-eigentum"
}, {
"title": "Compliance",
"link": "/de/dienstleistungen/compliance"
}, {
"title": "Investment- und Beteiligungsrecht",
"link": "/de/dienstleistungen/beteiligungsrecht"
}, {
"title": "Mergers & Acquisitions",
"link": "/de/dienstleistungen/mergers-and-acquisitions"
}, {
"title": "Immobilienrecht",
"link": "/de/dienstleistungen/immobilienrecht"
}, {
"title": "Internet- und Datenschutzrecht",
"link": "/de/dienstleistungen/internetrecht"
}, {
"title": "Gesellschaftsrecht",
"link": "/de/dienstleistungen/gesellschaftsrecht"
}, {
"title": "Handelsrecht",
"link": "/de/dienstleistungen/handelsrecht"
}, {
"title": "Arbeitsrecht",
"link": "/de/dienstleistungen/arbeitsrecht"
}, {
"title": "Bankrecht",
"link": "/de/dienstleistungen/bankrecht"
}, {
"title": "Vertragsrecht",
"link": "/de/dienstleistungen/vertragsrecht"
}, {
"title": "Wettbewerbsrecht",
"link": "/de/dienstleistungen/wettbewerbsrecht"
}]
}, {
"title": "Beliebte Projekte",
"link": "/de/beliebte-projekte",
"children": [{
"title": "Compliance",
"link": "/de/beliebte-projekte/compliance",
"children": [{
"title": "Haftungsrisiken für Geschäftsführern",
"link": "/de/beliebte-projekte/compliance/haftungsrisken-geschaeftsfuehrern"
}, {
"title": "Compliance-Prüfung KMU",
"link": "/de/beliebte-projekte/compliance/compliance-pruefung-kmu"
}]
}]
}],
"sign_in": "Login"
}
}, {
"lang": "en",
"lines": {
"menu": [{
"title": "How it works",
"link": "/en/how-it-works"
}, {
"title": "Features",
"link": "/en/features"
}, {
"title": "Services",
"link": "/en/services",
"children": [{
"title": "Intellectual property",
"link": "/en/services/intellectual-property"
}, {
"title": "Compliance",
"link": "/en/services/compliance"
}, {
"title": "Investment law",
"link": "/en/services/investment-law"
}, {
"title": "Mergers & Acquisitions",
"link": "/en/services/mergers-and-acquisitions"
}, {
"title": "Real estate law",
"link": "/en/services/real-estate-law"
}, {
"title": "Internet law and data privacy",
"link": "/en/services/internet-law"
}, {
"title": "Company law",
"link": "/en/services/company-law"
}, {
"title": "Trade law",
"link": "/en/services/trade-law"
}, {
"title": "Labour law",
"link": "/en/services/labour-law"
}, {
"title": "Bank law",
"link": "/en/services/bank-law"
}, {
"title": "Contract law",
"link": "/en/services/contract-law"
}, {
"title": "Competition law",
"link": "/en/services/competition-law"
}]
}, {
"title": "Popular Projects",
"link": "/en/popular-projects",
"children": [{
"title": "Compliance",
"link": "/en/popular-projects/compliance",
"children": [{
"title": "Haf eng",
"link": "/en/popular-projects/compliance/haf-eng"
}, {
"title": "Compliance eng",
"link": "/en/popular-projects/compliance/compliance-eng"
}]
}]
}],
"sign_in": "Sign in"
}
}]
};
function getUrl(pairUrl, currentLng, enMenu, deMenu, obj) {
for (let k in obj) {
if (!obj.hasOwnProperty(k)) continue
if (obj[k].link === pairUrl) {
if (currentLng === 'de') {
return enMenu[k].link // get en link equivlant
} else {
return deMenu[k].link // get de link equivlant
}
} else {
if (!obj[k].hasOwnProperty('children') || obj[k].children.length <= 0) continue;
var ret = getUrl(pairUrl, currentLng, enMenu[k].children, deMenu[k].children, obj[k].children);
if(typeof ret != 'undefined') return ret;
}
}
}
function getLanguagePair(currentLng, pairUrl) {
// 'find url in json tree'
var enMenu = linkTreeObject.langs[1].lines.menu
var deMenu = linkTreeObject.langs[0].lines.menu
let obj = {}
// find position in tree
if (currentLng === 'de') {
obj = deMenu
} else {
obj = enMenu
}
return getUrl(pairUrl, currentLng, enMenu, deMenu, obj)
}
//works
console.log(getLanguagePair("en", "/en/how-it-works"))
console.log(getLanguagePair("en", "/en/popular-projects"))
console.log(getLanguagePair("de", "/de/anleitung"))
console.log(getLanguagePair("de", "/de/beliebte-projekte"))
//fail
console.log(getLanguagePair("en", "/en/services/compliance"))
console.log(getLanguagePair("en", "/en/popular-projects/compliance"))
console.log(getLanguagePair("en", "/en/popular-projects/compliance/compliance-eng"))
Stack Overflow用户
发布于 2017-05-19 11:04:10
递归函数中存在一个问题。如果在第一个函数调用时不匹配url，则可以递归地再次调用函数，但不返回。
function get_10_recursive(number){
if(number>=10) return 10;
else return get_10_recursive(number++);
}在本例中，如果数字小于10，则递归调用该函数，直到它遇到返回语句，然后它会重新跟踪堆栈并返回正确的结果。如果删除第三行中的return语句，代码也会执行，但它只返回第一个调用的结果，这是未定义的。
代码中的问题是，如果在for循环中放置返回，循环就会被中断，并且不会检查下一个字符串，因此您必须将函数调用的结果存储在一个临时变量中，并且只有在它是真实的(也就是它不是未定义的)时才返回它。
您的getUrl函数如下所示：
function getUrl(pairUrl, currentLng, enMenu, deMenu, obj) {
for (var k in obj) {
if (obj[k].link === pairUrl) {
if (currentLng === 'de') {
return enMenu[k].link; // get en link equivlant
} else {
return deMenu[k].link; // get de link equivlant
}
} else {
if (obj[k].hasOwnProperty('children')){
var tmp = getUrl(pairUrl, currentLng, enMenu[k].children, deMenu[k].children, obj[k].children);
if(tmp) return tmp; // check if it found the match successfully
}
}
}
}PS:我记得if (!obj.hasOwnProperty(k)) continue是因为它没用
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/44067246
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