# FAQ

> Short answers about flagstaff — the runtime, modes, stdout versus stderr, Ink, CommonJS, colours and testing — each with where to read more.

Source: https://flagstaff.interlace.tools/docs/faq

## Why does `hoist()` take a runtime instead of reading `process`?

So the mode is decided once, by one rule, and so a test can pass a literal. The loop reads the
environment, whether stdout is a terminal, two streams and a clock from what you hand it, and
nothing else. [Getting started](/docs/getting-started#the-runtime) has a runtime for a real
process in a dozen lines; a burgee program already has one.

## Which mode will my program get?

The first that matches: `json` if you passed `{ json: true }`; `accessible` if `CLI_ACCESSIBLE`
is set; `tty` if stdout is a terminal; `ci` if `CI` is set; otherwise `pipe`. A CI job that
attaches a terminal therefore animates — the terminal check comes before `CI`. The table is on
[Getting started](/docs/getting-started#the-five-modes).

## Where does output go?

The terminal, pipe, CI and accessible modes write to **stdout**. `--json` writes its events to
**stderr**, so stdout is left for your program's own result. The drop-ins write where their
incumbents do: `flagstaff/ora` to stderr by default, as ora does.

## I print a spinner in a loop and my CI log has thousands of lines.

Off a terminal, each state that changes the text is one line. Update when the text is worth
reading — see [Progress in logs](/docs/recipes/progress-in-logs).

## Does it replace Ink?

No. flagstaff has no layout engine and no React; `box` and `table` measure, wrap and join
strings. It covers the widgets ora, log-update, boxen and cli-table3 cover, on one loop, with a
text form for each. A full-screen interactive interface is what Ink is built for, and flagstaff
is not.

## Can I use it from CommonJS?

Yes, on Node 20.19+ and 22.13+: the package is ESM with a `default` condition, so
`require('flagstaff/spinner')` loads it through `require(esm)`. `shape.test.ts` installs the
packed tarball and does exactly that.

## Why are my spinner's glyphs not coloured?

flagstaff paints through roundel's tokens, which are plain until your program calls `fly()`
from `roundel/theme`. After that, `NO_COLOR`, `--json` and a pipe nobody asked to colour still
turn colour off. See [NO_COLOR and accessibility](/docs/guides/accessibility).

## How do I test what my CLI prints?

Pass a runtime with `manualClock()` and streams that collect what is written; the terminal
transcript is then a fixed string. See [Testing terminal output](/docs/recipes/testing-output).

## Are the cli-spinners styles included?

No, and neither are cli-boxes' borders: two spinner styles and six borders ship built in.
`flagstaff/import` turns the corpus you already depend on into a plugin in one call —
[Plugins](/docs/guides/plugins#bringing-a-corpus).

## Is the ora drop-in exactly ora?

It passes all 99 cases of ora 9.4.1's own suite, and its behaviour is ora's to the byte,
including in a pipe. The differences that remain are listed on
[Compatibility](/docs/drop-ins#known-differences).