Fully asserted build

[Oleg Grenrus]

We could have the Bacon.js build with all runtime-checkable preconditions (e.g. parameter should be a function or a stream) asserted. We already have assert* we strip for production build. But we can assert more.

Related: #568

[Ville Lautanala]

Could the asserts use environment variables like React does? This would make it easier to have asserts in your development build, but strip them away in production with envify.

[Oleg Grenrus]

@lautis I'd rather write:

function foo(stream) {
  assertStream(stream);
  // ...
}

function assertStream(stream) {
  if (process.env.NODE_ENV === "development") {
    assert(stream instanceof EventStream):
  }
}

function foo(stream) {
  if (process.env.NODE_ENV === "development") {
    assertStream(stream):
  }
}

function assertStream(stream) {
  assert(stream instanceof EventStream);
}

If envify + uglify can minify the former version, than why so not. Actually if one could mark functions to be inlined by uglify (or something else), that would be awesome.

Sorry, to lazy to try myself.

[Ville Lautanala]

UglifyJS isn't able to remove calls to empty functions nor does it have inlining. To remove all traces of asserts with envify/uglifyjs, the latter form would have to be used. However, we could add guards to assert calls in assemble.js or let JS compilers optimise away empty functions.