react-bootstrap/src/utils/createChainedFunction.js

Bootstrap 3 components build with React

/**
 * Safe chained function
 *
 * Will only create a new function if needed,
 * otherwise will pass back existing functions or null.
 *
 * @param {function} one
 * @param {function} two
 * @returns {function|null}
 */
function createChainedFunction(one, two) {
  let hasOne = typeof one === 'function';
  let hasTwo = typeof two === 'function';

  if (!hasOne && !hasTwo) { return null; }
  if (!hasOne) { return two; }
  if (!hasTwo) { return one; }

  return function chainedFunction() {
    one.apply(this, arguments);
    two.apply(this, arguments);
  };
}

export default createChainedFunction;