empty.js•1.3 kB
var _curry1 = require('./internal/_curry1');
var _isArguments = require('./internal/_isArguments');
var _isArray = require('./internal/_isArray');
var _isObject = require('./internal/_isObject');
var _isString = require('./internal/_isString');
/**
* Returns the empty value of its argument's type. Ramda defines the empty
* value of Array (`[]`), Object (`{}`), String (`''`), and Arguments. Other
* types are supported if they define `<Type>.empty` and/or
* `<Type>.prototype.empty`.
*
* Dispatches to the `empty` method of the first argument, if present.
*
* @func
* @memberOf R
* @since v0.3.0
* @category Function
* @sig a -> a
* @param {*} x
* @return {*}
* @example
*
* R.empty(Just(42)); //=> Nothing()
* R.empty([1, 2, 3]); //=> []
* R.empty('unicorns'); //=> ''
* R.empty({x: 1, y: 2}); //=> {}
*/
module.exports = _curry1(function empty(x) {
return (
(x != null && typeof x.empty === 'function') ?
x.empty() :
(x != null && x.constructor != null && typeof x.constructor.empty === 'function') ?
x.constructor.empty() :
_isArray(x) ?
[] :
_isString(x) ?
'' :
_isObject(x) ?
{} :
_isArguments(x) ?
(function() { return arguments; }()) :
// else
void 0
);
});