mounted () {
    /* istanbul ignore else */
    if (!this.multiple && this.max) {
      console.warn('[Vue-Multiselect warn]: Max prop should not be used when prop Multiple equals false.');
    }
    if (
      this.preselectFirst &&
      !this.internalValue.length &&
      this.options.length
    ) {
      this.select(this.filteredOptions[0]);
    }
  }
Allows a custom function for sorting search/filtered results.
@default null
@type {Function}