_.negate(predicate)

_.negate(predicate)

function isEven(n) {
  return n % 2 == 0;
}
 
_.filter([1, 2, 3, 4, 5, 6], _.negate(isEven));
// => [1, 3, 5]

/**
 * Creates a function that negates the result of the predicate `func`. The
 * `func` predicate is invoked with the `this` binding and arguments of the
 * created function.
 *
 * @since 3.0.0
 * @category Function
 * @param {Function} predicate The predicate to negate.
 * @returns {Function} Returns the new negated function.
 * @example
 *
 * function isEven(n) {
 *   return n % 2 == 0
 * }
 *
 * filter([1, 2, 3, 4, 5, 6], negate(isEven))
 * // => [1, 3, 5]
 */
//将predicate方法返回的结果取反
function negate(predicate) {
  if (typeof predicate != 'function') {//如果predicate不是function，抛出错误
    throw new TypeError('Expected a function')
  }
  return function(...args) {//返回一个方法，这个方法将predicate的返回值取反
    return !predicate.apply(this, args)
  }
}

export default negate