# Incremental migration

> Move from chalk to roundel/chalk with one import, then to semantic tokens a file at a time, with both reading the same policy throughout.

Source: https://roundel.interlace.tools/docs/recipes/incremental-migration

## Step one: the import

```diff
- import chalk from 'chalk';
+ import chalk from 'roundel/chalk';
```

`roundel/chalk` passes chalk 6.0.0's own suite, so every call keeps its output. What changes is
underneath: the level now comes from the policy, so `NO_COLOR` is honoured and `--no-color`
beats an ambient `FORCE_COLOR` ([Compatibility](/docs/drop-ins#known-differences)).

`npx burgee migrate --dry-run` lists every import it would rewrite, and `npx burgee migrate`
rewrites them ([Migrate](https://burgee.interlace.tools/docs/migrate)).

## Step two: meanings, a file at a time

```diff
- import chalk from 'roundel/chalk';
- console.error(chalk.red(`missing ${chalk.bold('--name')}`));
+ import { error, flag } from 'roundel/tokens';
+ console.error(error(`missing ${flag('--name')}`));
```

Tokens are plain until the program calls `fly()` once at startup; add that before the first
file moves. From then on both styles read the same policy, so a file on `roundel/chalk` and a
file on tokens never disagree about whether this terminal gets colour.

## Step three: drop chalk

```bash
npm uninstall chalk
npm ls chalk
```

`npm ls` shows what still pulls chalk in transitively. An `overrides` entry pointing `chalk` at
`roundel` would resolve to the package root, not to `roundel/chalk`, so it cannot move those
copies; they move when the packages that depend on chalk do.