Assertions and error handling

[lazarljubenovic]

Something like this?

j.pipe(
  source,
  // definitely an `assert` namespace
  j.assert.notEmpty(),
  // maybe a few more inner namespaces for groups of related functions
  j.assert.length.atLeast(3),
  j.assert.each.satisfies(tg.isNumber), // type guards
  // not entirely sure what's needed here without some case studies
  j.catchError((error) => j.Empty()), // also not entirely sure if this is even possible
)

Assertions would be partial triggers -- they would never yield values through before understanding that the condition is satisfied. In other words, they should either behave like passThrough or throw an error. They can tweak the type information though (e.g. the satisfies from the example above.

[lazarljubenovic]

j.assert.each.satisfies would also be a great start of a chain when defining a custom operator using the point-free style (see #16). It will be possible to avoid the awkwardly placed type inside the first operator, and provide inline documentation.

Of course, it adds some overhead.