断言没有按预期工作

assert not working as expected

这是我用 transcrypt -b -n -m(版本 3.6.84)转译的 python 代码:

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')

当我在浏览器控制台中 运行 test_1/test_2 时,我得到了一个奇怪的行为:

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

为什么 assert 没有抛出异常?

来自issue 482的回答:

您需要 -da 开关来激活断言:

transcrypt -b -n -m -da

我测试过:

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()

它打印:

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

Transcrypt 中的许多东西都是可选的,以防止生成的膨胀 JavaScript。 一些功能由命令行开关控制:

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

某些功能(也)由 pragma 的(编译器指令)控制:

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