/** Error message constants. */ var FUNC_ERROR_TEXT = 'Expected a function'; /** * 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. * * @static * @memberOf _ * @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] */ function negate(predicate) { if (typeof predicate != 'function') { throw new TypeError(FUNC_ERROR_TEXT); } return function() { var args = arguments; switch (args.length) { case 0: return !predicate.call(this); case 1: return !predicate.call(this, args[0]); case 2: return !predicate.call(this, args[0], args[1]); case 3: return !predicate.call(this, args[0], args[1], args[2]); } return !predicate.apply(this, args); }; } module.exports = negate;