bdom-keep-order - a tool to add/remove sibling elements whilst keeping them in order

Motivation:

React handles fast dom updates by virtual dom comparison. This tool is part of an aim to eliminate the need for that and write fast and small single page apps utilising only the standard dom, by solving the very specific problem of keeping sibling elements in order by holding on to them even while they're not attached to the dom and adding them back in when needed.

A good example is routing. When a route matches a component should show. and when it doesn't it should be detached from the dom. If you have many elements in a list that show on same routes you run into the problem of losing the order of the components and you will need to keep the order in memory and then add/remove the elements accordingly. That's exactly what this tool does.

Installation

npm install --save bdom-keep-order

Usage

    import { keepOnParentStart } from 'bdom-keep-order'
    // or if you only need to support es6 compatible browsers
    // import { keepOnParentStart } from 'bdom-keep-order/es6'  

    const parent = document.createElement('ul')
    document.getElementsByTagName('body')[0].appendChild(parent)

    const children = [
      [ show => show === 'show a', document.createTextNode('SHOWING A') ],
      [ show => show === 'show b', document.createTextNode('SHOWING B') ],
      [ show => show === 'show a' || show === 'show b', 
        document.createTextNode('SHOW ON A AND B') ],
    ]
    const keeper = keepOnParentStart(parent, children)

    keeper.keep('show a')
    // SHOWING A
    // SHOW ON A AND B
    // Always show this

    keeper.keep('show b')
    // SHOWING B
    // SHOW ON A AND B
    // Always show this

    keeper.keep('show z')
    // Always show this

    children.pop()

    keeper.keep('show a')
    // SHOWING A
    // SHOW ON A AND B

    const reorderedChildren = [
        children[2],
        children[1],
        children[0],
        document.createTextNode("I'm new!"),
    ]

    // reset will try and perform the reordering of the nodes with minimal dom // edits, but it's alwasy better to reorder the original list manually if 
    // possible and avoid the comparison routine
    keeper.reset(reorderedChildren)

    // you will need to call keep after reset to see the expected result
    keeper.keep('show a')
    // SHOW ON A AND B
    // SHOWING A
    // I'm new!

build

npm run build

test

npm test