Jest: [Docs] Please document what ENV variables are set by Jest

[Akuukis]

🚀 Feature Proposal

Please document what ENV variables are set by Jest, and whenever users are supposed to use them or not.

Motivation

I'm trying to detect whenever runtime is within Jest environment or not.

Example

Jest sets the following ENV variables:

• JEST_WORKER_ID [number] Id of the Jest worker. Use it for ...
• ...

[SimenB]

You can use NODE_ENV - Jest sets it to test unless it's already set to something else

[Akuukis]

Oh, after you said that I explicitly searched docs for it and yes, indeed, under "Getting Started" > "Using Babel" > "Making your Babel config jest-aware" that's mentioned. Thank you, my current problem is solved!

I will leave this ticket open, because I do use also JEST_WORKER_ID and I believe it should appear in docs to understand whenever and how I should use it, as well I'm not aware of other global variables.

[jeysal]

Pretty sure that's also documented somewhere, but I agree an overview
somewhere might make sense.

On Tue, 20 Aug 2019, 10:32 Akuukis, [e-mail] wrote:

Oh, after you said that I explicitly searched docs for it and yes, indeed,
under "Getting Started" > "Using Babel" > "Making your Babel config
jest-aware" that's mentioned. Thank you, my current problem is solved!

I will leave this ticket open, because I do use also JEST_WORKER_ID and I
believe it should appear in docs to understand whenever and how I should
use it, as well I'm not aware of other global variables.

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[Akuukis]

JEST_WORKER_ID doesn't show up in doc search, but suggests --maxWorkers instead.

[jeysal]

Found it :D https://jestjs.io/docs/en/dynamodb
But yeah that's not a good location, there should be a central list of env variables or something ^^

[mojoaxel]

You can use NODE_ENV - Jest sets it to test unless it's already set to something else

@SimenB This is no longer the case since the update to babel@7 :disappointed:

[stdavis]

I'd love to help out with this. @jeysal: do you have a thought as to where in the docs the list of environment variables should be? I was thinking maybe a new page under the "API Reference" section? Or just add it to Getting Started, although it doesn't seem like a getting-started thing? Maybe add a section to Globals?