给定字符串值，如何查找它是否大于Typescript枚举类型中的值？

Question

I am implementing a very basic user roles, to disallow users with lower privileges from seeing certain parts of the site. For example, the current user must be an Executive or higher or a given div will not render.

I have a string value from the database representing the user's level eg "Executive", or "Owner". I want to compare that to an enumerated type I have created:

enum systemRoles {
  Staff,
  Manager,
  DeptMgr,
  Executive,
  Owner
}

...so that in an html template I can say:

<div *ngIf="userLevelIsAtLeast(systemRoles.Executive)">

to only render that div if the user has high enough privileges. So, my pseudocode is:

<div *ngIf="userLevelIsAtLeast(systemRoles.Executive)>You are an executive or higher!</div>
.
.
userLevelIsAtLeast(user_level) {
return currentUser().level >= user_level
}

To be clear: if currentUser.level == "Executive" , this should return true. if currentUser.level == "Owner" , this should return true. if currentUser.level == "Staff" , this should return false.

I'm stuck re-re-reading the typescript enum documentation and I cluttered up a similar, but not duplicate question, by getting stuck in semantics just trying to make an enum type compile. So, this question gets to the real issue I'm having: currentUser().level is a string, but I need to match it to a value in the enumerated type and compare that to the enumerated value it should be greater than or equal to.

Answer 1

you can set the equivalent strnig to the enum types

enum systemRoles {
  Staff='Staff',
  Manager='Manager',
  DeptMgr='DeptMgr',
  Executive='Executive',
  Owner='Owner'
}

Answer 2

First off, you should store it as the enum if you can (there is no reason to do a string that I can think of).

Second, as long as the names match exactly you can just index into the enum "object" so:

return systemRoles[currentUser().level] >= user_level

Will work. Indexing with a string will return the value, and indexing with a value will return the string. And as always; make sure you validate the permissions on the backend! The UI cannot be counted on for true security.