/** Used as the internal argument placeholder. */
const PLACEHOLDER = '__lodash_placeholder__';

/**
 * Replaces all `placeholder` elements in `array` with an internal placeholder
 * and returns an array of their indexes.
 *
 * @private
 * @param {Array} array The array to modify.
 * @param {*} placeholder The placeholder to replace.
 * @returns {Array} Returns the new array of placeholder indexes.
 */
function replaceHolders(array, placeholder) {
  let index = -1;
  const length = array.length;
  let resIndex = 0;
  const result = [];

  while (++index < length) {
    const value = array[index];
    if (value === placeholder || value === PLACEHOLDER) {
      array[index] = PLACEHOLDER;
      result[resIndex++] = index;
    }
  }
  return result;
}

export default replaceHolders;