memoize.js•1.23 kB
var _arity = require('./internal/_arity');
var _curry1 = require('./internal/_curry1');
var _has = require('./internal/_has');
var toString = require('./toString');
/**
* Creates a new function that, when invoked, caches the result of calling `fn`
* for a given argument set and returns the result. Subsequent calls to the
* memoized `fn` with the same argument set will not result in an additional
* call to `fn`; instead, the cached result for that set of arguments will be
* returned.
*
* @func
* @memberOf R
* @since v0.1.0
* @category Function
* @sig (*... -> a) -> (*... -> a)
* @param {Function} fn The function to memoize.
* @return {Function} Memoized version of `fn`.
* @example
*
* var count = 0;
* var factorial = R.memoize(n => {
* count += 1;
* return R.product(R.range(1, n + 1));
* });
* factorial(5); //=> 120
* factorial(5); //=> 120
* factorial(5); //=> 120
* count; //=> 1
*/
module.exports = _curry1(function memoize(fn) {
var cache = {};
return _arity(fn.length, function() {
var key = toString(arguments);
if (!_has(key, cache)) {
cache[key] = fn.apply(this, arguments);
}
return cache[key];
});
});