Simple Flag

A javascript flag system based on bitwise function. The system use a enumerator in base 2 (1, 2, 4, 8...) to check if a value provided has the flag set.

Installation

To install with npm or yarn, use the following command:

Yarn

yarn add simple-flag

NPM

npm install simple-flag

Usage

const SimpleFlag = require('simple-flag');
 
const userPermissionEnum = {
  addUser: 1,
  removeUser: 2,
  updateUser: 4,
  viewUsers: 8,
};
 
const permissionValue = 13; // Data that can come from Database
 
const userPermission = new SimpleFlag(userPermissionEnum, permissionValue);
 
// User have the permission to add User
if(userPermission.hasFlag(userEnum.addUser)) { // true
  // Can add a user
}
 
// User do not have the permission to Remove User
if(userPermission.hasFlag(userEnum.removeUser)) { // false
  // Can Remove a user
}
 
// User have the permission to Update User
if(userPermission.hasFlag(userEnum.updateUser)) { // true
  // Can update a user
}
 
// User have the permission to View Users
if(userPermission.hasFlag('viewUsers')) { // true
  // Can view all users
}

Methods

hasFlag* - Check if the flag has been set.

hasAllFlags** - Check if all flags provided (array) has been set.

hasAnyFlag** - Check if any of the flags provided (array) has been set.

*: Accepts a flag as variable which can be a number (enum.property) or the name of the property.

**: Accepts an array of flags as variable which can be a number (enum.property) or a string (name of the property).

Options

The constructor accept a third variable which is an object. The object accepts the following properties:

• validateEnum: True by default. Simple-flag will validate everything inside the enumerator defined in the constructor. If you know what you are doing and don't need any validation, just set to false.

Comming soon..

• AddFlag() - Ability to add a property and value to the flag enumerator.
• RemoveFlag() - Ability to remove a property and value to the flag enumerator.
• updateFlag() - Ability to update a value to a specific property in the flag enumerator.

Licence

MIT