negate.js•1.08 kB
/** 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;