Looping through functions until value is not null, ramda js

Question

I want a function that returns a value when a function returns a value which is not null.

const getSomeValue = R.filter(...);

const getSomeOtherValue = R.propEq('name');

The R.until function is probably the one to use.

Some pseudo code:

R.until(R.isNotNull, R...[getSomeValue, getSomeOtherValue]);

So run through the functions until the returned value is not null.

I don't find any suitable function in the Ramda docs to do this.

Any ideas?

can you provide a small example with input / output? that would help in understanding what you want to achieve — Turtlefight, Aug 16 '19 at 17:43
Hmm, niether `propEq('name')` nor `filter` would return `null`. Please provide actual functions and inputs you have. — Yury Tarabanko, Aug 16 '19 at 18:40

score 0 · Answer 1 · answered Aug 16 '19 at 17:29

If you don't mind to also ignore falsy values (false, undefined, 0, etc...) then you could use R.either:

const first = () => {
  console.log("first");
  return null;
};
const second = () => {
  console.log("second");
  return {a: "banana"};
};
const third = () => {
  console.log("third");
  return {a: "chicken"};
};

const fn = R.either(first, second, third);
console.log(fn());

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Looping through functions until value is not null, ramda js

1 Answers1