lodash/_toFunction.js

define(['./identity'], function(identity) {

  /**
   * Converts `value` to a function if it's not one.
   *
   * @private
   * @param {*} value The value to process.
   * @returns {Function} Returns the function.
   */
  function toFunction(value) {
    return typeof value == 'function' ? value : identity;
  }

  return toFunction;
});