---
title: "Offer a new version instead of overwriting"
description: "Leave the existing file untouched and write the new version beside it with present."
source: "https://jostraca.org/how-to/offer-a-new-version/"
---

# Offer a new version instead of overwriting

Leave the existing file untouched and write the new version beside it with present.

Rendered from [`docs/how-to/offer-a-new-version.md`](https://github.com/jostraca/jostraca/blob/master/docs/how-to/offer-a-new-version.md) in the generator repository — where a correction belongs, and where the test suite runs every example on this page or states why it does not.

`present` writes the new version to a `.new` sibling and leaves the existing file exactly as it is. The user decides.

**`present` needs `write: false`.** The flags are checked in order and `write` is checked first, so `present: true` on its own does nothing at all and the file is overwritten. This is the single easiest way to misconfigure regeneration:

```js
import { appendFileSync } from 'node:fs'
import { Jostraca, Project, File, Content } from 'jostraca'

const jostraca = Jostraca({
  existing: { txt: { write: false, present: true } },
})

const run = (body) => jostraca.generate({ folder: './out' }, () => {
  Project({}, () => File({ name: 'config.sh' }, () => Content(body)))
})

await run('PORT=8080\n')
appendFileSync('./out/config.sh', 'DEBUG=1\n')
await run('PORT=9090\n')
```

```text
config.new.sh
config.sh
```

`config.sh` is untouched:

```text
PORT=8080
DEBUG=1
```

and `config.new.sh` holds what the generator wanted to write:

```text
PORT=9090
```

The run reports these paths in `result.files.presented`, so a wrapper command can list them and tell the user what is waiting.

`present` is also the one mode that still acts on a file the user has taken over with `JOSTRACA_PROTECT`: the protected file keeps its bytes, and the `.new` sidecar is still written. That is deliberate—somebody who has taken a file over may still want to see what they are declining.

## See also

-   [Let a user take a file over](https://jostraca.org/how-to/let-a-user-take-a-file-over).
-   [Show a diff instead of writing](https://jostraca.org/how-to/show-a-diff-instead-of-writing) when the difference matters more than the new version.