tryCatch.js•1.3 kB
var _arity = require('./internal/_arity');
var _concat = require('./internal/_concat');
var _curry2 = require('./internal/_curry2');
/**
* `tryCatch` takes two functions, a `tryer` and a `catcher`. The returned
* function evaluates the `tryer`; if it does not throw, it simply returns the
* result. If the `tryer` *does* throw, the returned function evaluates the
* `catcher` function and returns its result. Note that for effective
* composition with this function, both the `tryer` and `catcher` functions
* must return the same type of results.
*
* @func
* @memberOf R
* @since v0.20.0
* @category Function
* @sig (...x -> a) -> ((e, ...x) -> a) -> (...x -> a)
* @param {Function} tryer The function that may throw.
* @param {Function} catcher The function that will be evaluated if `tryer` throws.
* @return {Function} A new function that will catch exceptions and send then to the catcher.
* @example
*
* R.tryCatch(R.prop('x'), R.F, {x: true}); //=> true
* R.tryCatch(R.prop('x'), R.F, null); //=> false
*/
module.exports = _curry2(function _tryCatch(tryer, catcher) {
return _arity(tryer.length, function() {
try {
return tryer.apply(this, arguments);
} catch (e) {
return catcher.apply(this, _concat([e], arguments));
}
});
});