[英]JavaScript - recursive looping through object
我正在嘗試為練習制作一個簡單的ACL。
我想遍歷我的對象數據,如果我的currentViewer有父,我想將他的路徑(在我的對象中訪問)添加到arrayAccess。
因此,如果我的觀眾是用戶,他的accessArray應該是["", home]
,如果他是管理員,它將是["", home, user]
,如果他是客人,它將只是[""]
。
如何以遞歸方式執行此操作,因此我不必創建數千個for循環?
我試圖在checkParent()
調用checkParent()
,但它只會使我的循環不定式。 我很抱歉,如果這是一個愚蠢的問題,我在JS開始。
var currentViewer = "user"; var data = { users: [{ role: "guest", access: "" }, { role: "user", access: "home", parent: "guest" }, { role: "admin", access: "user", parent: "user" } ] }; var accessArray = []; function checkRole() { var users = data.users; for (var i = 0; i < users.length; i++) { if (currentViewer === users[i].role) { accessArray.push(users[i].access); console.log(accessArray); function checkParent() { if (users[i].parent) { for (var j = 0; j < users.length; j++) { if (users[i].parent === users[j].role) { accessArray.push(users[j].access); console.log(accessArray); } } } }; checkParent(); } }; }; checkRole();
有很多方法可以做到這一點。 簡單的方法就是使哈希容易查找並在循環中引用父項並推送。
var data = { users : [ { role:"guest" , access:"" }, { role:"user" , access:"home", parent: "guest" }, { role:"admin" , access:"user", parent: "user" } ] }; var roleHash = data.users.reduce(function(o, i) { o[i.role] = i; return o; }, {}); function getAccessRoles(roleKey) { var role = roleHash[roleKey]; var roles = [role.access]; while (role.parent) { role = roleHash[role.parent]; roles.unshift(role.access); } return roles; } console.log("admin", getAccessRoles("admin")); console.log("user", getAccessRoles("user")); console.log("guest", getAccessRoles("guest"));
你可以試試這個:
var data = {
users : [
{ role:"guest" , access:"" },
{ role:"user" , access:"home", parent: "guest" },
{ role:"admin" , access:"user", parent: "user" }
]
};
var currentUser = "admin";
var arr = [];//array that you need
var defineAccess = function(item){
if(item.parent){
var index = data.users.map(function(e) { return e.role; }).indexOf(item.parent);
defineAccess(data.users[index]); //recursive calling
arr.push(data.users[index].access);
}
}
data.users.forEach(function(item){
if(currentUser === item.role){
arr.push(item.access);
defineAccess(item);
}
})
console.log(arr); //final output array
我不認為“遞歸”本身應該是一個目標......為什么不創建一個角色及其屬性的Map,並使用parent
屬性從這個地圖中檢索一個新項目,直到你不能?
var data = { users: [{ role: "guest", access: "" }, { role: "user", access: "home", parent: "guest" }, { role: "admin", access: "user", parent: "user" } ] }; var roles = new Map(data.users.map(u => [u.role, u])); var getAccess = function(role) { var access = []; var current = roles.get(role); while (current) { access.push(current.access); current = roles.get(current.parent); } return access.reverse(); } console.log("guest", getAccess("guest")) console.log("user", getAccess("user")) console.log("admin", getAccess("admin"))
首先構建一個對象模型,然后問題很簡單。
var data = { users: [ { role: "guest", access: "" }, { role: "user", access: "home", parent: "guest" }, { role: "admin", access: "user", parent: "user" } ] }; var users = data.users.reduce(function (roles, user) { roles[user.role] = user; return roles; }, {}); var accessList = data.users.map(function (user) { var all = []; do { all.unshift(user.access); user = users[user.parent]; } while (user); return all; }); console.log(accessList);
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