var before = require('./before');

/**
 * Creates a function that is restricted to invoking `func` once. Repeat calls
 * to the function return the value of the first call. The `func` is invoked
 * with the `this` binding of the created function.
 *
 * @static
 * @memberOf _
 * @type Function
 * @category Function
 * @param {Function} func The function to restrict.
 * @returns {Function} Returns the new restricted function.
 * @example
 *
 * var initialize = _.once(createApplication);
 * initialize();
 * initialize();
 * // `initialize` invokes `createApplication` once
 */
function once(func) {
  return before(func, 2);
}

module.exports = once;
