mcp-appstore

var _arity = require('./internal/_arity'); var _curry1 = require('./internal/_curry1'); /** * Accepts a function `fn` and returns a function that guards invocation of * `fn` such that `fn` can only ever be called once, no matter how many times * the returned function is invoked. The first value calculated is returned in * subsequent invocations. * * @func * @memberOf R * @since v0.1.0 * @category Function * @sig (a... -> b) -> (a... -> b) * @param {Function} fn The function to wrap in a call-only-once wrapper. * @return {Function} The wrapped function. * @example * * var addOneOnce = R.once(x => x + 1); * addOneOnce(10); //=> 11 * addOneOnce(addOneOnce(50)); //=> 11 */ module.exports = _curry1(function once(fn) { var called = false; var result; return _arity(fn.length, function() { if (called) { return result; } called = true; result = fn.apply(this, arguments); return result; }); });