JavaScript - 通过对象递归循环

Question

I'm trying to make a simple ACL just for practice.

I want to loop through my object data and if my currentViewer has a parent I want to add his path (access in my object) to arrayAccess.

So if my viewer is user his accessArray should be ["", home] , if he's admin it would be ["", home, user] and if he's a guest it will be only [""] .

How to do it in a recursive way, so I don't have to create thousands of for loops?

I was trying calling a checkParent() inside my checkParent() , but it only makes my loop infinitive. I'm sorry if it's a silly question, I'm very beginning in JS.

 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(); 

Answer 1

There are a bunch of ways to do it. Simple way is just make a hash for easy look up and reference the parents on a loop and push.

 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")); 

Answer 2

You can try this:

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

Answer 3

I don't think "recursiveness" should be a goal on its own... Why not create a Map of roles and their properties and use the parent property to retrieve a new item from this map, until you can't?

 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")) 

Answer 4

build an object model first,then the problem is simple.

 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);