MyMongodb/node_modules/popper.js/src/modifiers/flip.js

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import getOppositePlacement from '../utils/getOppositePlacement';
import getOppositeVariation from '../utils/getOppositeVariation';
import getPopperOffsets from '../utils/getPopperOffsets';
import runModifiers from '../utils/runModifiers';
import getBoundaries from '../utils/getBoundaries';
import isModifierEnabled from '../utils/isModifierEnabled';
import clockwise from '../utils/clockwise';

const BEHAVIORS = {
  FLIP: 'flip',
  CLOCKWISE: 'clockwise',
  COUNTERCLOCKWISE: 'counterclockwise',
};

/**
 * @function
 * @memberof Modifiers
 * @argument {Object} data - The data object generated by update method
 * @argument {Object} options - Modifiers configuration and options
 * @returns {Object} The data object, properly modified
 */
export default function flip(data, options) {
  // if `inner` modifier is enabled, we can't use the `flip` modifier
  if (isModifierEnabled(data.instance.modifiers, 'inner')) {
    return data;
  }

  if (data.flipped && data.placement === data.originalPlacement) {
    // seems like flip is trying to loop, probably there's not enough space on any of the flippable sides
    return data;
  }

  const boundaries = getBoundaries(
    data.instance.popper,
    data.instance.reference,
    options.padding,
    options.boundariesElement,
    data.positionFixed
  );

  let placement = data.placement.split('-')[0];
  let placementOpposite = getOppositePlacement(placement);
  let variation = data.placement.split('-')[1] || '';

  let flipOrder = [];

  switch (options.behavior) {
    case BEHAVIORS.FLIP:
      flipOrder = [placement, placementOpposite];
      break;
    case BEHAVIORS.CLOCKWISE:
      flipOrder = clockwise(placement);
      break;
    case BEHAVIORS.COUNTERCLOCKWISE:
      flipOrder = clockwise(placement, true);
      break;
    default:
      flipOrder = options.behavior;
  }