@shopify/draggable/build/esnext/Draggable/Plugins/Mirror/Mirror.mjs

The JavaScript Drag & Drop library your grandparents warned you about.

import { AbstractPlugin } from '../../../shared/AbstractPlugin/AbstractPlugin.mjs';
import { MirrorCreateEvent, MirrorCreatedEvent, MirrorAttachedEvent, MirrorMoveEvent, MirrorDestroyEvent, MirrorMovedEvent } from './MirrorEvent/MirrorEvent.mjs';

const onDragStart = Symbol('onDragStart');
const onDragMove = Symbol('onDragMove');
const onDragStop = Symbol('onDragStop');
const onMirrorCreated = Symbol('onMirrorCreated');
const onMirrorMove = Symbol('onMirrorMove');
const onScroll = Symbol('onScroll');
const getAppendableContainer = Symbol('getAppendableContainer');

const defaultOptions = {
  constrainDimensions: false,
  xAxis: true,
  yAxis: true,
  cursorOffsetX: null,
  cursorOffsetY: null,
  thresholdX: null,
  thresholdY: null
};

class Mirror extends AbstractPlugin {

  constructor(draggable) {
    super(draggable);

    this.options = {
      ...defaultOptions,
      ...this.getOptions()
    };

    this.scrollOffset = {
      x: 0,
      y: 0
    };

    this.initialScrollOffset = {
      x: window.scrollX,
      y: window.scrollY
    };
    this[onDragStart] = this[onDragStart].bind(this);
    this[onDragMove] = this[onDragMove].bind(this);
    this[onDragStop] = this[onDragStop].bind(this);
    this[onMirrorCreated] = this[onMirrorCreated].bind(this);
    this[onMirrorMove] = this[onMirrorMove].bind(this);
    this[onScroll] = this[onScroll].bind(this);
  }

  attach() {
    this.draggable.on('drag:start', this[onDragStart]).on('drag:move', this[onDragMove]).on('drag:stop', this[onDragStop]).on('mirror:created', this[onMirrorCreated]).on('mirror:move', this[onMirrorMove]);
  }

  detach() {
    this.draggable.off('drag:start', this[onDragStart]).off('drag:move', this[onDragMove]).off('drag:stop', this[onDragStop]).off('mirror:created', this[onMirrorCreated]).off('mirror:move', this[onMirrorMove]);
  }

  getOptions() {
    return this.draggable.options.mirror || {};
  }
  [onDragStart](dragEvent) {
    if (dragEvent.canceled()) {
      return;
    }
    if ('ontouchstart' in window) {
      document.addEventListener('scroll', this[onScroll], true);
    }
    this.initialScrollOffset = {
      x: window.scrollX,
      y: window.scrollY
    };
    const {
      source,
      originalSource,
      sourceContainer,
      sensorEvent
    } = dragEvent;

    this.lastMirrorMovedClient = {
      x: sensorEvent.clientX,
      y: sensorEvent.clientY
    };
    const mirrorCreateEvent = new MirrorCreateEvent({
      source,
      originalSource,
      sourceContainer,
      sensorEvent,
      dragEvent
    });
    this.draggable.trigger(mirrorCreateEvent);
    if (isNativeDragEvent(sensorEvent) || mirrorCreateEvent.canceled()) {
      return;
    }
    const appendableContainer = this[getAppendableContainer](source) || sourceContainer;
    this.mirror = source.cloneNode(true);
    const mirrorCreatedEvent = new MirrorCreatedEvent({
      source,
      originalSource,
      sourceContainer,
      sensorEvent,
      dragEvent,
      mirror: this.mirror
    });
    const mirrorAttachedEvent = new MirrorAttachedEvent({
      source,
      originalSource,
      sourceContainer,
      sensorEvent,
      dragEvent,
      mirror: this.mirror
    });
    this.draggable.trigger(mirrorCreatedEvent);
    appendableContainer.appendChild(this.mirror);
    this.draggable.trigger(mirrorAttachedEvent);
  }
  [onDragMove](dragEvent) {
    if (!this.mirror || dragEvent.canceled()) {
      return;
    }
    const {
      source,
      originalSource,
      sourceContainer,
      sensorEvent
    } = dragEvent;
    let passedThreshX = true;
    let passedThreshY = true;
    if (this.options.thresholdX || this.options.thresholdY) {
      const {
        x: lastX,
        y: lastY
      } = this.lastMirrorMovedClient;
      if (Math.abs(lastX - sensorEvent.clientX) < this.options.thresholdX) {
        passedThreshX = false;
      } else {
        this.lastMirrorMovedClient.x = sensorEvent.clientX;
      }
      if (Math.abs(lastY - sensorEvent.clientY) < this.options.thresholdY) {
        passedThreshY = false;
      } else {
        this.lastMirrorMovedClient.y = sensorEvent.clientY;
      }
      if (!passedThreshX && !passedThreshY) {
        return;
      }
    }
    const mirrorMoveEvent = new MirrorMoveEvent({
      source,
      originalSource,
      sourceContainer,
      sensorEvent,
      dragEvent,
      mirror: this.mirror,
      passedThreshX,
      passedThreshY
    });
    this.draggable.trigger(mirrorMoveEvent);
  }
  [onDragStop](dragEvent) {
    if ('ontouchstart' in window) {
      document.removeEventListener('scroll', this[onScroll], true);
    }
    this.initialScrollOffset = {
      x: 0,
      y: 0
    };
    this.scrollOffset = {
      x: 0,
      y: 0
    };
    if (!this.mirror) {
      return;
    }
    const {
      source,
      sourceContainer,
      sensorEvent
    } = dragEvent;
    const mirrorDestroyEvent = new MirrorDestroyEvent({
      source,
      mirror: this.mirror,
      sourceContainer,
      sensorEvent,
      dragEvent
    });
    this.draggable.trigger(mirrorDestroyEvent);
    if (!mirrorDestroyEvent.canceled()) {
      this.mirror.remove();
    }
  }
  [onScroll]() {
    this.scrollOffset = {
      x: window.scrollX - this.initialScrollOffset.x,
      y: window.scrollY - this.initialScrollOffset.y
    };
  }

  [onMirrorCreated]({
    mirror,
    source,
    sensorEvent
  }) {
    const mirrorClasses = this.draggable.getClassNamesFor('mirror');
    const setState = ({
      mirrorOffset,
      initialX,
      initialY,
      ...args
    }) => {
      this.mirrorOffset = mirrorOffset;
      this.initialX = initialX;
      this.initialY = initialY;
      this.lastMovedX = initialX;
      this.lastMovedY = initialY;
      return {
        mirrorOffset,
        initialX,
        initialY,
        ...args
      };
    };
    mirror.style.display = 'none';
    const initialState = {
      mirror,
      source,
      sensorEvent,
      mirrorClasses,
      scrollOffset: this.scrollOffset,
      options: this.options,
      passedThreshX: true,
      passedThreshY: true
    };
    return Promise.resolve(initialState)

    .then(computeMirrorDimensions).then(calculateMirrorOffset).then(resetMirror).then(addMirrorClasses).then(positionMirror({
      initial: true
    })).then(removeMirrorID).then(setState);
  }

  [onMirrorMove](mirrorEvent) {
    if (mirrorEvent.canceled()) {
      return null;
    }
    const setState = ({
      lastMovedX,
      lastMovedY,
      ...args
    }) => {
      this.lastMovedX = lastMovedX;
      this.lastMovedY = lastMovedY;
      return {
        lastMovedX,
        lastMovedY,
        ...args
      };
    };
    const triggerMoved = args => {
      const mirrorMovedEvent = new MirrorMovedEvent({
        source: mirrorEvent.source,
        originalSource: mirrorEvent.originalSource,
        sourceContainer: mirrorEvent.sourceContainer,
        sensorEvent: mirrorEvent.sensorEvent,
        dragEvent: mirrorEvent.dragEvent,
        mirror: this.mirror,
        passedThreshX: mirrorEvent.passedThreshX,
        passedThreshY: mirrorEvent.passedThreshY
      });
      this.draggable.trigger(mirrorMovedEvent);
      return args;
    };
    const initialState = {
      mirror: mirrorEvent.mirror,
      sensorEvent: mirrorEvent.sensorEvent,
      mirrorOffset: this.mirrorOffset,
      options: this.options,
      initialX: this.initialX,
      initialY: this.initialY,
      scrollOffset: this.scrollOffset,
      passedThreshX: mirrorEvent.passedThreshX,
      passedThreshY: mirrorEvent.passedThreshY,
      lastMovedX: this.lastMovedX,
      lastMovedY: this.lastMovedY
    };
    return Promise.resolve(initialState).then(positionMirror({
      raf: true
    })).then(setState).then(triggerMoved);
  }

  [getAppendableContainer](source) {
    const appendTo = this.options.appendTo;
    if (typeof appendTo === 'string') {
      return document.querySelector(appendTo);
    } else if (appendTo instanceof HTMLElement) {
      return appendTo;
    } else if (typeof appendTo === 'function') {
      return appendTo(source);
    } else {
      return source.parentNode;
    }
  }
}

function computeMirrorDimensions({
  source,
  ...args
}) {
  return withPromise(resolve => {
    const sourceRect = source.getBoundingClientRect();
    resolve({
      source,
      sourceRect,
      ...args
    });
  });
}

function calculateMirrorOffset({
  sensorEvent,
  sourceRect,
  options,
  ...args
}) {
  return withPromise(resolve => {
    const top = options.cursorOffsetY === null ? sensorEvent.clientY - sourceRect.top : options.cursorOffsetY;
    const left = options.cursorOffsetX === null ? sensorEvent.clientX - sourceRect.left : options.cursorOffsetX;
    const mirrorOffset = {
      top,
      left
    };
    resolve({
      sensorEvent,
      sourceRect,
      mirrorOffset,
      options,
      ...args
    });
  });
}

function resetMirror({
  mirror,
  source,
  options,
  ...args
}) {
  return withPromise(resolve => {
    let offsetHeight;
    let offsetWidth;
    if (options.constrainDimensions) {
      const computedSourceStyles = getComputedStyle(source);
      offsetHeight = computedSourceStyles.getPropertyValue('height');
      offsetWidth = computedSourceStyles.getPropertyValue('width');
    }
    mirror.style.display = null;
    mirror.style.position = 'fixed';
    mirror.style.pointerEvents = 'none';
    mirror.style.top = 0;
    mirror.style.left = 0;
    mirror.style.margin = 0;
    if (options.constrainDimensions) {
      mirror.style.height = offsetHeight;
      mirror.style.width = offsetWidth;
    }
    resolve({
      mirror,
      source,
      options,
      ...args
    });
  });
}

function addMirrorClasses({
  mirror,
  mirrorClasses,
  ...args
}) {
  return withPromise(resolve => {
    mirror.classList.add(...mirrorClasses);
    resolve({
      mirror,
      mirrorClasses,
      ...args
    });
  });
}

function removeMirrorID({
  mirror,
  ...args
}) {
  return withPromise(resolve => {
    mirror.removeAttribute('id');
    delete mirror.id;
    resolve({
      mirror,
      ...args
    });
  });
}

function positionMirror({
  withFrame = false,
  initial = false
} = {}) {
  return ({
    mirror,
    sensorEvent,
    mirrorOffset,
    initialY,
    initialX,
    scrollOffset,
    options,
    passedThreshX,
    passedThreshY,
    lastMovedX,
    lastMovedY,
    ...args
  }) => {
    return withPromise(resolve => {
      const result = {
        mirror,
        sensorEvent,
        mirrorOffset,
        options,
        ...args
      };
      if (mirrorOffset) {
        const x = passedThreshX ? Math.round((sensorEvent.clientX - mirrorOffset.left - scrollOffset.x) / (options.thresholdX || 1)) * (options.thresholdX || 1) : Math.round(lastMovedX);
        const y = passedThreshY ? Math.round((sensorEvent.clientY - mirrorOffset.top - scrollOffset.y) / (options.thresholdY || 1)) * (options.thresholdY || 1) : Math.round(lastMovedY);
        if (options.xAxis && options.yAxis || initial) {
          mirror.style.transform = `translate3d(${x}px, ${y}px, 0)`;
        } else if (options.xAxis && !options.yAxis) {
          mirror.style.transform = `translate3d(${x}px, ${initialY}px, 0)`;
        } else if (options.yAxis && !options.xAxis) {
          mirror.style.transform = `translate3d(${initialX}px, ${y}px, 0)`;
        }
        if (initial) {
          result.initialX = x;
          result.initialY = y;
        }
        result.lastMovedX = x;
        result.lastMovedY = y;
      }
      resolve(result);
    }, {
      frame: withFrame
    });
  };
}

function withPromise(callback, {
  raf = false
} = {}) {
  return new Promise((resolve, reject) => {
    if (raf) {
      requestAnimationFrame(() => {
        callback(resolve, reject);
      });
    } else {
      callback(resolve, reject);
    }
  });
}

function isNativeDragEvent(sensorEvent) {
  return /^drag/.test(sensorEvent.originalEvent.type);
}

export { Mirror as default, defaultOptions, getAppendableContainer, onDragMove, onDragStart, onDragStop, onMirrorCreated, onMirrorMove, onScroll };