Code coverage report for src/planks.js

# all files / src/ planks.js

23.98% Statements 41/171
21.69% Branches 18/83
25% Functions 7/28
10.08% Lines 13/129
5 statements, 1 function, 3 branches Ignored

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     import React from 'react';IEE
    import Plank from './plank';EI

    /**
     * Container for planks. Handles the sizing, positioning, and responsiveness for all individual planks.
     *
     * @param Object props.options
     */
    export default class Planks extends React.Component {
        constructor(props) {
            super(props);

            let breakpointKey = this.getCurrentBreakpointKey();
            // let planksRendered = {};

            /*planksRendered[breakpointKey] = {
                hiddenPlanksRendered: false,
                heightsSet: false
            };*/

            this.validateConfigOptions();

            this.state = {
                plankWidths: {},                    // Caches all the plank widths per breakpoint
                plankHeights: {},                   // Caches and used to determine when to unhide
                plankPosition: {},                  // The calculated positions for each plank
                containerWidth: 0,                  // Used to determine widths of planks based on current screen breakpoint
                containerHeights: {},               // Must set height because container element is absolute
                breakpointKey: breakpointKey,       // Current responsive breakpoint
                allPlanksRendered: {}               // Caches when to unhide by breakpoint
            };
        }

        /**
         * When this component first mounts, no data has been loaded yet. Therefore, no dimensions of the children
         * components can be known. The objective here is to simply get the widths of the child planks so that they can
         * be quickly rendered.
         */
        componentDidMount() {
            // console.log('[PLANKS CONTAINER] COMPONENT DID MOUNT...');
            let containerWidth = this.getPlankContainerWidth();
            let plankWidths = this.getSinglePlankWidths(containerWidth);
            let planksRendered = this.state.allPlanksRendered;

            // console.log('[PLANKS CONTAINER] INITIAL CONTAINER WIDTH: ' + containerWidth);
            // console.log('[PLANKS CONTAINER] INITIAL PLANK WIDTH: ' + plankWidths[this.state.breakpointKey]);

            // Event listener to calculate dimensions and positions on re-size. Caches results for faster subsequent
            // rendering.
            window.addEventListener('resize', this.handleResize.bind(this));

            this.setState({
                plankWidths: plankWidths,
                containerWidth: containerWidth,
                allPlanksRendered: planksRendered
            });

            // Force update so that all children's state gets synced with the new width.
            // console.log('[PLANKS CONTAINER] FORCE UPDATE');
            this.forceUpdate();
        }

        /**
         * There are two phases of rendering individual child planks:
         *      1. When the width is first set and they are rendered hidden and without positioning.
         *      2. When all their heights have been received and positions have been calculated.
         */
        shouldComponentUpdate() {
            // console.log('[PLANKS CONTAINER] SHOULD COMPONENT UPDATE?');
            if (!this.state.allPlanksRendered[this.state.containerWidth] ||
                !this.state.allPlanksRendered[this.state.containerWidth].hiddenPlanksRendered) {
                // console.log('[PLANKS CONTAINER] YES, INVISIBLE PLANKS HAVE NOT BEEN RENDERED YET');
                return true;
            }
            if (!this.state.allPlanksRendered[this.state.containerWidth] ||
                !this.state.allPlanksRendered[this.state.containerWidth].heightsSet) {
                // console.log('[PLANKS CONTAINER] NO, ALL HEIGHTS HAVE NOT BEEN RECEIVED. BYPASSING UPDATE');
                return false;
            }
            return true;
        }

        componentWillUnmount() {
        }

        /**
         * TODO -- move this into it's own module that you include outside of Plank's scope.
         *
         * Checks to make sure the options passed in as this.props of this component are valid. Issue warnings and use
         * defaults if they are not valid.
         */
        validateConfigOptions() {
            // TODO -- check to make sure keys are screen widths in numbers. issue a warning if they aren't. they don't
            // have to be in order.
        }

        /**
         * @return Number   the current width of the referenced container element.
         */
        getPlankContainerWidth() {
            return this._planksContainer.offsetWidth;
        }

        /**
         * Returns the current breakpoint key. Use this only when absolutely necessary such as on initial page load and
         * when a responsive screen re-size has occured.
         */
        getCurrentBreakpointKey() {
            let screenWidth = document.body.offsetWidth;
            let breakpointKey;
            let optionKeys = [];

            // Since for...in loops do not guarantee order, extract the keys
            // into an array that can then be sorted in ascending order. If the current screen size is larger than any
            // defined key, the column count will be associated to the largest key.
            for (let key in this.props.options.breakpoints) {
                optionKeys.push(key);
            }

            optionKeys.sort((a, b) => +a - +b);
            breakpointKey = optionKeys[optionKeys.length - 1];

            // If optionKeys is length 0, then we will use the largest key as assigned by the expression above,
            // otherwise take the 0 index value as that by definition is the nearest breakpoint to the current screen size.
            optionKeys = optionKeys.filter((item) => screenWidth < item);
            if (optionKeys.length > 0) {
                breakpointKey = optionKeys[0];
            }

            return breakpointKey;
        }

        /**
         * Checks if width has previously been calculated and returns the cached value. Otherwise this calculates the width
         * taking into account the current breakpoint, number of columns associated to the breakpoint, and horizontal
         * padding.
         *
         * @param   Number      containerWidth      the current container width
         * @param   String      nextBreakpointKey   hacky optional param to set the next value when a resize occurs
         * @return  Object      plankWidths         cache of breakpoint keys to plank widths
         */
        getSinglePlankWidths(containerWidth, nextBreakpointKey) {
            let plankWidths = this.state.plankWidths;
            let breakpointKey = nextBreakpointKey || this.state.breakpointKey;
            let numColumns;
            let singlePlankWidth;

            // Check for cached value
            if (plankWidths[containerWidth] && plankWidths[containerWidth].length > 0) {
                return plankWidths[containerWidth];
            }

            // To get the width of a single plank, the horizontal padding must be accounted for.
            numColumns = this.props.options.breakpoints[breakpointKey + ''];

            // 16px === 1rem
            let hPadding = this.props.options.horizontalPadding;
            let unitRatio = this.props.options.unitType === 'rem' ? 16 : 1;
            singlePlankWidth = (containerWidth - ((numColumns - 1) * hPadding * unitRatio)) / numColumns / unitRatio;

            // Cache the current value against the breakpoint key
            plankWidths[containerWidth] = singlePlankWidth;

            return plankWidths;
        }

        /**
         * For optimization we need a flag to determine when all the hidden planks have been rendered. This allows us to
         * skip re-rendering until all the hidden planks have been rendered.
         */
        handleAllHiddenPlanksRendered() {
            let planksRendered = this.state.allPlanksRendered;

            // console.log('[PLANKS CONTAINER] LAST HIDDEN PLANK RENDERED');
            if (!planksRendered[this.state.containerWidth]) {
                planksRendered[this.state.containerWidth] = {};
            }
            planksRendered[this.state.containerWidth].hiddenPlanksRendered = true;
            this.setState({ allPlanksRendered: planksRendered });
            return true;
        }

        /**
         * Screen resizes must handle the re-ordering of cards. If this ordering has already occurred for the existing
         * data set, use a locally cached version of that particular ordering.
         *
         * TODO -- handle orientationchange event for mobile
         */
        handleResize() {
            let containerWidth = this.getPlankContainerWidth();

            // Screen widths alone do not determine when a responsive change has occured. Responsiveness is a set of fixed
            // container widths that exist over ranges of screen sizes. Handling resize is more optimal when
            // calculations only occur when container width changes. Additionally, setting the current
            // breakpointKey should only occur here and in the constructor.
            if (this.state.containerWidth !== containerWidth) {
                // console.log('[PLANKS CONTAINER] RESIZE DETECTED...');
                let breakpointKey = this.getCurrentBreakpointKey();
                // console.log('breakpointKey: ', breakpointKey);
                // console.log('containerWidth: ', containerWidth);
                let planksRendered = this.state.allPlanksRendered;
                let plankWidths = this.getSinglePlankWidths(containerWidth, breakpointKey);

                // console.log('planksWidths', plankWidths);
                // console.log('planksRendered');
                console.table(planksRendered);
                if (planksRendered[breakpointKey] !== undefined) {
                    this.setState({
                        breakpointKey: breakpointKey,
                        containerWidth: containerWidth
                    });
                    return; // Cache exists. Do nothing.
                }

                planksRendered[breakpointKey] = {
                    hiddenPlanksRendered: false,
                    heightsSet: false
                };

                this.setState({
                    breakpointKey: breakpointKey,
                    plankWidths: plankWidths,
                    containerWidth: containerWidth,
                    allPlanksRendered: planksRendered
                });
            }
        }

        /**
         * A callback that receives the hidden child element's height. When all heights are received, we can then calculate
         * their correct positioning and set their visibility. This callback should execute one time per element render.
         * This means that responsiveness should trigger a new render. However, we have to also account for cached values.
         */
        receiveChildHeight(key, childHeight) {
            let plankHeights = this.state.plankHeights;
            let planksRendered = this.state.allPlanksRendered;
            let renderAllPlanks;

            // console.log('[PLANKS CONTAINER] RECEIVING CHILD HEIGHT:');
            // console.log('[PLANKS CONTAINER] KEY: ' + key, 'HEIGHT: ' + childHeight);

            if (plankHeights[this.state.containerWidth] === undefined) {
                plankHeights[this.state.containerWidth] = {};
            }

            // It is very normal for updated heights to come back to us. This could indicated another image loaded, an
            // image failing to load, or even new content. In this case we must force update if all the other heights
            // have already been received.
            let heightExists = plankHeights[this.state.containerWidth][key] || false;

            plankHeights[this.state.containerWidth][key] = childHeight;

            this.setState({ plankHeights: plankHeights });

            if (heightExists && this.state.allPlanksRendered[this.state.containerWidth].heightsSet) {
                // console.log('[PLANKS CONTAINER] UPDATING EXISTING HEIGHT. FORCE UPDATE');
                this.setPlankPositioning();
                this.forceUpdate();
            }

            // Render planks when all the heights have been received.
            renderAllPlanks = Object.keys(plankHeights[this.state.containerWidth]).length === this.props.children.length;

            // Initialize the rendering flags that corresponds to the two phases of child plank rendering.
            if (!planksRendered[this.state.containerWidth]) {
                planksRendered[this.state.containerWidth] = {
                    hiddenPlanksRendered: false,
                    heightsSet: false
                };
            }

            // once we have all the heights of each plank, we can now calculate their absolute positioning.
            if (renderAllPlanks) {
                this.setPlankPositioning();
                planksRendered[this.state.containerWidth].heightsSet = true;
            }

            this.setState({
                allPlanksRendered: planksRendered
            });
        }

        /**
         * Set the plank positioning. Position sorting occurs here.
         */
        setPlankPositioning() {
            let plankPosition = this.state.plankPosition;

            if (!plankPosition[this.state.containerWidth]) {
                plankPosition[this.state.containerWidth] = {};
            }

            let numColumns = this.props.options.breakpoints[this.state.breakpointKey];
            let columnHeights = [];
            let colHeightPadding = []; // Keeps track of the accumulated vertical padding;

            for (let i = 0; i < numColumns; i++) {
                columnHeights[i] = colHeightPadding[i] = 0;
            }

            // iterate from left col to right col looking for the shortest col.
            // if all cols are equal height, place in the left most col.
            let [i, col, left] = [0, 0, 0];
            let plankWidth = this.state.plankWidths[this.state.containerWidth];
            let hPadding = this.props.options.horizontalPadding;
            let vPadding = this.props.options.verticalPadding;
            let unitRatio = this.props.options.unitType === 'rem' ? 16 : 1;
            for (; i < this.props.children.length; i++) {
                let plankHeight = this.state.plankHeights[this.state.containerWidth][i];
                let positionStyle = {};
                let shortestColHeight = Math.min.apply(Math, columnHeights);
                let shortestColIndex = columnHeights.indexOf(Math.min.apply(Math, columnHeights));
                let leftProperty = shortestColIndex * plankWidth + shortestColIndex * hPadding;
                let topProperty = shortestColHeight / unitRatio + colHeightPadding[shortestColIndex];

                positionStyle = {
                    left: leftProperty,
                    top: topProperty
                };

                plankPosition[this.state.containerWidth][i] = positionStyle;
                columnHeights[shortestColIndex] += plankHeight;
                colHeightPadding[shortestColIndex] += vPadding;

                if (col === numColumns - 1) {
                    col = left = 0;
                }
            }

            let greatestHeight = columnHeights.reduce((prev, cur) => prev > cur ? prev : cur);
            let containerHeights = this.state.containerHeights;

            greatestHeight += Math.max.apply(Math, colHeightPadding) * unitRatio;
            containerHeights[this.state.containerWidth] = greatestHeight;

            this.setState({
                plankPosition: plankPosition,
                containerHeights: containerHeights
            });
        }

        getPlankStyles(index) {
            if (!this.state.allPlanksRendered[this.state.containerWidth] ||
                !this.state.allPlanksRendered[this.state.containerWidth].heightsSet) {
                return {
                    position: 'absolute',
                    visibility: 'hidden',
                    width: this.state.plankWidths[this.state.containerWidth] + this.props.options.unitType
                };
            } else {
                let positionStyles = this.state.plankPosition[this.state.containerWidth][index + ''];

                return {
                    position: 'absolute',
                    visibility: 'visible',
                    width: this.state.plankWidths[this.state.containerWidth] + this.props.options.unitType,
                    left: positionStyles.left + 'rem',
                    top: positionStyles.top + 'rem'
                };
            }
        }

        /**
         * Child styles are fetched upon rendering in order to allow for responsiveness. These styles have already been
         * calculated and are simply set here to render based on the current responsive breakpoint.
         */
        render() {
            // console.log('[PLANKS CONTAINER] CONTAINER RENDERING...');
            // console.log('[PLANKS CONTAINER] CURRENT CHILD PLANK WIDTH: ' + this.state.plankWidths[this.state.breakpointKey]);

            let containerStyle = {
                height: this.state.containerHeights[this.state.containerWidth],
                position: 'relative'
            };
            let planks;

            if (React.Children.count(this.props.children) > 1) {
                planks = this.props.children.map((plank, index) => {
                    let styles = this.getPlankStyles(index);
                    let lastPlankHandler = index === React.Children.count(this.props.children) - 1
                        ? this.handleAllHiddenPlanksRendered.bind(this)
                        : (() => null);

                    return (
                        <Plank
                            key={ index }
                            index={ index }
                            plankStyles={ styles }
                            plankWidth={ this.state.plankWidths[this.state.containerWidth] }
                            updateChildHeight={ this.receiveChildHeight.bind(this) }
                            handleLastPlank={ lastPlankHandler }
                        >
                            { plank }
                        </Plank>
                    );
                });
            } else {
                planks = this.props.children;
            }

            return (
                <div style={ containerStyle } ref={ (c) => this._planksContainer = c }>{ planks }</div>
            );
        }
    }

    Planks.propTypes = { options: React.PropTypes.object };
    Planks.defaultProps = {
        options: {
            'breakpoints': {
                '544': 1,
                '768': 2,
                '992': 3,
                '1200': 4
            },
            'horizontalPadding': 1,
            'verticalPadding': 1,
            'unitType': 'rem'
        }
    };