1. Install

npm install acl-matrix

2. Require it

const AclMatrix = require('acl-matrix');

const roles = ['admin', 'member', 'guest'];
const resources = ['blog', 'comment'];
const allows = ['get', 'add', 'update', 'delete'];

// Each element in matrix stores the permissions of a role to a resource.
const matrix = [
    //   admin        member         guest
    [[1, 1, 1, 1], [1, 0, 1, 1], [1, 0, 0, 0]], // blog
    [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 0]], // comment
];

const acl = new AclMatrix(roles, resources, allows, matrix);

// 0
acl.isAllowed('member', 'blog', 'add');

// 1
acl.isAllowed('member', 'blog', 'get');

• roles are the types of user trying to access resources
• allows describes the oprations user will need to do
• matrix describes the allows relation between roles and resources;
• third dimension of the matrix is an array of 0 and 1s, the length of array should equal to allows's. This array describes the permissions.

For example: in the above sample code, matrix[0][2] ([1, 0, 0, 0]) means the guest role is able to 'get' the 'blog' resource, but not others.

• Row number of matrix should eauql to resources length;
• Collum number of matrix should eauql to role length;
• Element number of matrix should eauql to allows length;

node_acl is good, but it acquires database to store the acls. And it is relatively hard to mantain and update acl using node_acl.

Benefits of using acl-matrix:

1. Three dimensional matrix is the simplest way to store acl;
2. Simple to config and simple for future change;
3. No dependency, acl matrix can be easily shared between frontend and backend;
4. Performance: no database needed, checking permissions is justing reading elemet in array

1. By using node_acl you are able to save relations between users and roles. You will need to store the role of the user youself using acl-matrix
2. By default, permissions of each roles are fixed, which is suitable for most projects. But if you want to allow user define the acl, you will need to store multiple acl matrices

Add more method for the class maybe?