Filtering Array<unknown> to a type?

Is this the best way to filter an Array of unknown to an ark type?:

type transaction = type(...);
const items: unknown[] = ...;
const transactions = items
  .filter(transaction.allows)
  .map(transaction);

type transaction = type(...);
const items: unknown[] = ...;
const transactions = items
  .filter(transaction.allows)
  .map(transaction);

I don't need to throw when something in items doesn't match. I just want to filter.

2 Replies

Generally flatMap is a good way to filter and map with a single function in JS:

const transactions = items.flatMap(item => {
    const out = transaction(item)
    return out instanceof type.errors ? [] : [out]
})

const transactions = items.flatMap(item => {
    const out = transaction(item)
    return out instanceof type.errors ? [] : [out]
})

AlanOP•3w ago

Makes sense, thanks!