Expected behavior when there is no output TTY

[nickwesselman]

We have a command with long-running output in a <Static> which we would like our users to be able to pipe into a command like more or less. However ink does not seem to handle piped output / lack of TTY as there are ANSI escapes in the output. You also see re-renders for non-Static elements.

> npm run example examples/static | more

> [email protected] example
> NODE_NO_WARNINGS=1 node --loader ts-node/esm examples/static


Completed tests: 0
ESC[2KESC[1AESC[2KESC[1AESC[2KESC[G✔ Test #1

Completed tests: 1
ESC[2KESC[1AESC[2KESC[1AESC[2KESC[G✔ Test #2

Completed tests: 2
ESC[2KESC[1AESC[2KESC[1AESC[2KESC[G✔ Test #3

Completed tests: 3
ESC[2KESC[1AESC[2KESC[1AESC[2KESC[G✔ Test #4

Completed tests: 4
ESC[2KESC[1AESC[2KESC[1AESC[2KESC[G✔ Test #5

Completed tests: 5
ESC[2KESC[1AESC[2KESC[1AESC[2KESC[G✔ Test #6

Completed tests: 6
ESC[2KESC[1AESC[2KESC[1AESC[2KESC[G✔ Test #7

Completed tests: 7
ESC[2KESC[1AESC[2KESC[1AESC[2KESC[G✔ Test #8

Completed tests: 8
ESC[2KESC[1AESC[2KESC[1AESC[2KESC[G✔ Test #9

Completed tests: 9
ESC[2KESC[1AESC[2KESC[1AESC[2KESC[G✔ Test #10

Completed tests: 10

If you simulate a CI run via environment variable, it actually behaves exactly as I would expect:

> CI=1 npm run example examples/static | more

> [email protected] example
> NODE_NO_WARNINGS=1 node --loader ts-node/esm examples/static

✔ Test #1
✔ Test #2
✔ Test #3
✔ Test #4
✔ Test #5
✔ Test #6
✔ Test #7
✔ Test #8
✔ Test #9
✔ Test #10

Completed tests: 10

Shouldn't ink behave the same way for !process.stdout.isTTY as it would for isInCi? Is support for piping output not a common requirement in ink-based CLIs?

[nickwesselman]

I'm thinking that all the isInCI behaviors in ink.tsx should be possible to enable or disable with a render option, but would default to on if isInCi || !process.stdout.isTTY.

[sindresorhus]

That makes sense to me 👍

[nickwesselman]

Proposed a fix in #669