env() removes capitalization from camel case variable names

[pownkel]

In the update to v16, it looks like the behavior of env() changed to convert all env variable names to lowercase. Here's an example to illustrate:

process.env.camelCaseArg = 'value';
process.env.lowercasearg = 'value';

const envArgs = yargs().env().argv;

console.log(`lower case: ${envArgs.lowercasearg}`);
console.log(`camel case: ${envArgs.camelCaseArg}`);
console.log(`camel case variable with lower case name: ${envArgs.camelcasearg}`);

Running this on v15.4.0 prints

lower case: value
camel case: value
camel case variable with lower case name: undefined

While in v16.0.0 and later, the same code prints

lower case: value
camel case: undefined
camel case variable with lower case name: value

Updating to v16 broke some of our code as our camel case env variables were no longer found under their original names. I'm not sure whether the change was intentional, but the API documentation for .env() still shows camel case env variable names in the argv object, which is misleading.

[pitgrap]

We got the same problem in our CI after updating to v16.

environmentVariable: TEST_DATA_CLI_testPropertiesUrl
Code: yargs.env("TEST_DATA_CLI").demandCommand(1, "You need at least one command before moving on.")...
Log:

[INFO] test-data import
[INFO] ...
[INFO] Missing required argument: testPropertiesUrl
[INFO] error Command failed with exit code 1.

Took me a while to find this issue as the cause for the failing CI. We have reverted to v15.

[bcoe]

@pitgrap @pownkel thank you for the bug report, I'm pretty sure this will end up being related to my reimplementing our camel case logic in v16 -- if you get a chance to dig into it, patches are very much welcome.

[pitgrap]

@bcoe can you give me a code pointer? I tried to find the PR, which introduced this bug, but gave up after 10min search. :-/

[bcoe]

@pitgrap I implemented camel-case, and de-camel-case here:

https://github.com/yargs/yargs-parser/blob/master/lib/string-utils.ts#L26

When I ported the library to ESM.

[Ivan-Strahovsky]

@bcoe I have fix in my local branch, how can I open PR for to review?

[bcoe]

this should be fixed in the latest release.