Ramda: if func returns truthy value, use it in compose, else return as is

Question

is there any neat Ramda way of writing something like this:

 const ifOkCompose = (...args) => {
            const r = foo(...args);

            if (r) {
                return compose(bar1, bar2)(r);
            }

            return r;
        };

If foo() returns truthy value, send it to compose, otherwise just return it. There is 'when', but it would return arguments instead of returned value of 'foo(...)'.

In other words, I have a function foo which may return undefined, I use it in compose as compose(bar1, bar2, foo). If foo(...) returns undefined I want to kick out of compose and just return undefined.

Answer 1

的docs示例R.composeWith接近您想要的。

const composeWhileNotNil = R.composeWith((f, res) => R.isNil(res) ? res : f(res))

composeWhileNotNil([bar1, bar2, foo])

最大的不同是，这将停止任何无响应的合成，而不仅仅是第一个。显然，如果您只想停止undefined而不想停止，则可以轻松地对其进行更改null。