get-z-index

This is library to help you to manage your z indices in declarative way.

Example

Let's assume that your application has four layers: page, header, modals and notifications.

Lets assume that header should be above the page. Modal above the header and all notifications above modal and header.

const RULES = [
  ['page', 'header'],
  ['header', 'modals'],
  ['modals', 'notifications'],
];

While we have this RULES array we can create function getZIndex which will return z-index for each layer based on this rules.

import { compile } from 'get-z-index';

const getZIndex = compile(RULES);

And now we can use it:

getZIndex('page'); // => 0
getZIndex('header'); // => 1
getZIndex('modals'); // => 2
getZIndex('notifications'); // => 3

Sometimes there is need to be able to show several modals on the screen and several notifications.

Lets define maximum amount of modals and notifications in the dictionary:

const MAX_NUMBER_DICT = {
  modals: 3,
  notifications: 10,
};

Lets create another version of getZIndex which will use this information:

import { compile } from 'get-z-index';

const getZIndex = compile(RULES, MAX_NUMBER_DICT);

Lets calculate all possible zIndices for all layers and items inside layer with usage of second parameter of getZIndex function - index.

getZIndex('page'); // => 0
getZIndex('header'); // => 1
getZIndex('modals'); // => 2
getZIndex('modals', 1); // => 3, z-index for second modal above the first modal
getZIndex('modals', 2); // => 4
getZIndex('notifications'); // => 5

Also it's possible that sometimes someone else code controls z-index of the component. For example modals are from some library. And inside the library we have z-index equal to 1000. We can define it with usage of the last parameter - predefinedZIndices.

const getZIndex = compile(
  [
    ['page', 'modal'],
    ['modal', 'notification'],
    ['notification', 'tooltips'],
  ],
  null,
  { modal: 1000 }
);

And we can use it:

getZIndex('page'); // 0
getZIndex('modal'); // 1000
getZIndex('notification'); // 1001
getZIndex('tooltips'); // 1002

Pretty much it! Use and enjoy!