assert not working as expected

Question

Here is the python code I transcrypted with transcrypt -b -n -m (version 3.6.84) :

def test_1():
    console.log('before assert')
    assert False, "False fails"
    console.log('we should not see that if assert fails as expected')


def test_2():
    console.log('before assert')
    try:
        assert False, "False fails"
    except AssertionError as exception:
        console.log('we should see that since we catch the assertion error')
    console.log('after assert')

When I run test_1/test_2 in the browser console, I get a strange behavior :

> mymodule.test_1()
before assert
we should not see that if assert fails as expected
<- undefined
> mymodule.test_2()
before assert
after assert
<- undefined

Why no exception are raised with assert ?

Answer 1

Answer from issue 482 :

You need the -da switch to activate assertions:

transcrypt -b -n -m -da

I've tested:

def test_1():
    console.log('before assert')
    assert False, "False fails"
    console.log('we should not see that if assert fails as expected')

def test_2():
    console.log('before assert')
    try:
        assert False, "False fails"
    except AssertionError as exception:
        console.log('we should see that since we catch the assertion error')
    console.log('after assert')

try:    
    test_1()
except AssertionError as exception:
    console.log('we should see this')

test_2()

It prints:

before assert
we should see this
before assert
we should see that since we catch the assertion error
after assert

Many things in Transcrypt are optional, to prevent bloat of the generated JavaScript. Some features are controlled by command line switches:

http://www.transcrypt.org/docs/html/installation_use.html#available-command-line-switches

Some features are (also) controlled by pragma's (compiler directives):

http://www.transcrypt.org/docs/html/special_facilities.html#the-pragma-mechanism