Pen Settings

HTML

CSS

CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URL's added here will be added as <link>s in order, and before the CSS in the editor. If you link to another Pen, it will include the CSS from that Pen. If the preprocessor matches, it will attempt to combine them before processing.

+ add another resource

JavaScript

Babel is required to process package imports. If you need a different preprocessor remove all packages first.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource

Behavior

Save Automatically?

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.

HTML Settings

Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

HTML

            
              <!--

This is a proof of concept based on Cheng Lou's
totally amazing React Motion library:
https://github.com/chenglou/react-motion

Really just a proof of concept to see if I could get
it working across multiple columns (i.e. no source order 
reflowing) for a kanban / trello list app I'm working on.

However, I couldn't elegantly solve the issue of variable 
item heights in calculateVisiblePositions(), so have decided 
to drop this as it is and move over to react-dnd instead.

If anyone ever figures out how to do this with variable 
item heights, please let me know!

-->

<h1 class="title">Drag &amp; Drop Grid Layout in React</h1>
<div id="react-root"></div>
            
          
!

CSS

            
              html {
	width: 100%;
	height: 100%;
	background: radial-gradient(ellipse at top, #e66465, transparent),
            radial-gradient(ellipse at bottom, #4d9f0c, transparent);
}

.title {
	margin-top: 1.25em;
	color: #eee;
	text-align: center;
	text-shadow: 1px 1px 0 black;
}

.items {
	padding: 21px;
}

.item {
	width: calc((100% / 3) - 26px);
	height: 90px;
	padding: 2.125em 0 1.25em;
	user-select: none;
	position: absolute;
	border-radius: 3px;
	box-shadow: 0 2px 2px 0 rgba(0, 0, 0, 0.2);
	background: rgba(255, 255, 255, 0.75);
	transition: background-color 0.1s ease-in-out;
	cursor: grab;
	text-align: center;

	&.is-active {
		background: rgba(255, 255, 255, 0.9);
		cursor: grabbing;
	}
}
            
          
!

JS

            
              const dataStructure = [ // structure that models our initial rendered view of items
    [0, 1, 2],
    [3, 4, 5, 6, 7],
    [8, 9, 10, 11]
]

const reinsert = (array, colFrom, rowFrom, colTo, rowTo) => {
    const _array = array.slice(0);
    const val = _array[colFrom][rowFrom];
    _array[colFrom].splice(rowFrom, 1);
    _array[colTo].splice(rowTo, 0, val);
    calculateVisiblePositions(_array);
    return _array;
}

const gutterPadding = 21;
const clamp = (n, min, max) => Math.max(Math.min(n, max), min);
const getColumnWidth = () => (window.innerWidth / dataStructure.length) - (gutterPadding / dataStructure.length); // spread columns over available window width
const height = 110; // crappy fixed item height :(

let width = getColumnWidth(),
    layout = null;

// items are ordered by their index in this visual positions array
const calculateVisiblePositions = (newOrder) => {
    width = getColumnWidth();
    layout = newOrder.map((column, col) => {
       return _.range(column.length + 1).map((item, row) => {
           return [width * col, height * row];
       });
   });
}

// define spring motion opts
const springSetting1 = {stiffness: 180, damping: 10};
const springSetting2 = {stiffness: 150, damping: 16};

const List = React.createClass({
    getInitialState() {
        return {
            mouse: [0, 0],
            delta: [0, 0], // difference between mouse and item position, for dragging
            lastPress: null, // key of the last pressed component
            currentColumn: null,
            isPressed: false,
            order: dataStructure, // index: visual position. value: component key/id
            isResizing: false
        };
    },

    componentWillMount() {
        this.resizeTimeout = null;
        calculateVisiblePositions(dataStructure);
    },

    componentDidMount() {
        window.addEventListener('touchmove', this.handleTouchMove);
        window.addEventListener('mousemove', this.handleMouseMove);
        window.addEventListener('touchend', this.handleMouseUp);
        window.addEventListener('mouseup', this.handleMouseUp);
        window.addEventListener('resize', this.handleResize);
    },

    componentWillUnmount() {
        window.removeEventListener('resize', this.handleResize);
    },

    handleTouchStart(key, currentColumn, pressLocation, e) {
        this.handleMouseDown(key, currentColumn, pressLocation, e.touches[0]);
    },

    handleTouchMove(e) {
        e.preventDefault();
        this.handleMouseMove(e.touches[0]);
    },

    handleMouseMove({pageX, pageY}) {
        const {order, lastPress, currentColumn: colFrom, isPressed, delta: [dx, dy]} = this.state;
        if (isPressed) {
            const mouse = [pageX - dx, pageY - dy];
            const colTo = clamp(Math.floor((mouse[0] + (width / 2)) / width), 0, 2);
            const rowTo = clamp(Math.floor((mouse[1] + (height / 2)) / height), 0, 100);
            const rowFrom = order[colFrom].indexOf(lastPress);
            const newOrder = reinsert(order, colFrom, rowFrom, colTo, rowTo);
            this.setState({
                mouse,
                order: newOrder,
                currentColumn: colTo
            });
        }
    },

    handleMouseDown(key, currentColumn, [pressX, pressY], {pageX, pageY}) {
        this.setState({
            lastPress: key,
            currentColumn,
            isPressed: true,
            delta: [pageX - pressX, pageY - pressY],
            mouse: [pressX, pressY],
        });
    },

    handleMouseUp() {
        this.setState({
            isPressed: false,
            delta: [0, 0]
        });
    },

    handleResize() {
        clearTimeout(this.resizeTimeout);
        this.applyResizingState(true);
        // resize one last time after resizing stops, as sometimes this can be a little janky sometimes...
        this.resizeTimeout = setTimeout(() => this.applyResizingState(false), 100);
    },

    applyResizingState(isResizing) {
        this.setState({ isResizing });
        calculateVisiblePositions(dataStructure);
    },

    render() {
        const { order, lastPress, currentColumn, isPressed, mouse, isResizing } = this.state;
        return (
            <div className="items">
                {order.map( (column, colIndex) => {
                    return (
                        column.map( (row) => {
                            let style,
                                x,
                                y,
                                visualPosition = order[colIndex].indexOf(row),
                                isActive = (row === lastPress && colIndex === currentColumn && isPressed);

                            if(isActive) {
                                [x, y] = mouse;
                                style = {
                                    translateX: x,
                                    translateY: y,
                                    scale: ReactMotion.spring(1.1, springSetting1)
                                };
                            } else if(isResizing) {
                                [x, y] = layout[colIndex][visualPosition];
                                style = {
                                    translateX: x,
                                    translateY: y,
                                    scale: 1
                                };
                            } else {
                                [x, y] = layout[colIndex][visualPosition];
                                style = {
                                    translateX: ReactMotion.spring(x, springSetting2),
                                    translateY: ReactMotion.spring(y, springSetting2),
                                    scale: ReactMotion.spring(1, springSetting1)
                                };
                            }

                            return (
                                <ReactMotion.Motion key={row} style={style}>
                                    {({translateX, translateY, scale}) =>
                                    <div
                                        onMouseDown={this.handleMouseDown.bind(null, row, colIndex, [x, y])}
                                        onTouchStart={this.handleTouchStart.bind(null, row, colIndex, [x, y])}
                                        className={isActive ? 'item is-active' : 'item'}
                                        style={{
                                            WebkitTransform: `translate3d(${translateX}px, ${translateY}px, 0) scale(${scale})`,
                                            transform: `translate3d(${translateX}px, ${translateY}px, 0) scale(${scale})`,
                                            zIndex: (row === lastPress && colIndex === currentColumn) ? 99 : visualPosition,
                                        }}>Item {row + 1}</div>
                                    }
                                </ReactMotion.Motion>
                            )
                        })
                    )
                })}
            </div>
        )
    }
});

ReactDOM.render(<List />, document.getElementById('react-root'));
            
          
!
999px

Console