react-bootstrap-typeahead/es/utils/defaultSelectHint.js

import isSelectable from './isSelectable';
export default function defaultSelectHint(e, selectHint) {
  var shouldSelectHint = false;

  if (e.key === 'ArrowRight') {
    // For selectable input types ("text", "search"), only select the hint if
    // it's at the end of the input value. For non-selectable types ("email",
    // "number"), always select the hint.
    shouldSelectHint = isSelectable(e.currentTarget) ? e.currentTarget.selectionStart === e.currentTarget.value.length : true;
  }

  if (e.key === 'Tab') {
    // Prevent input from blurring on TAB.
    e.preventDefault();
    shouldSelectHint = true;
  }

  return selectHint ? selectHint(shouldSelectHint, e) : shouldSelectHint;
}