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

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import isNumeric from '../utils/isNumeric';
import getClientRect from '../utils/getClientRect';
import find from '../utils/find';

/**
 * Converts a string containing value + unit into a px value number
 * @function
 * @memberof {modifiers~offset}
 * @private
 * @argument {String} str - Value + unit string
 * @argument {String} measurement - `height` or `width`
 * @argument {Object} popperOffsets
 * @argument {Object} referenceOffsets
 * @returns {Number|String}
 * Value in pixels, or original string if no values were extracted
 */
export function toValue(str, measurement, popperOffsets, referenceOffsets) {
  // separate value from unit
  const split = str.match(/((?:\-|\+)?\d*\.?\d*)(.*)/);
  const value = +split[1];
  const unit = split[2];

  // If it's not a number it's an operator, I guess
  if (!value) {
    return str;
  }

  if (unit.indexOf('%') === 0) {
    let element;
    switch (unit) {
      case '%p':
        element = popperOffsets;
        break;
      case '%':
      case '%r':
      default:
        element = referenceOffsets;
    }

    const rect = getClientRect(element);
    return rect[measurement] / 100 * value;
  } else if (unit === 'vh' || unit === 'vw') {
    // if is a vh or vw, we calculate the size based on the viewport
    let size;
    if (unit === 'vh') {
      size = Math.max(
        document.documentElement.clientHeight,
        window.innerHeight || 0
      );
    } else {
      size = Math.max(
        document.documentElement.clientWidth,
        window.innerWidth || 0
      );
    }
    return size / 100 * value;
  } else {
    // if is an explicit pixel unit, we get rid of the unit and keep the value
    // if is an implicit unit, it's px, and we return just the value
    return value;