---
title: "Skip files when copying"
description: "Keep editor backups, caches and named paths out of a copied tree."
source: "https://jostraca.org/how-to/skip-files-when-copying/"
---

# Skip files when copying

Keep editor backups, caches and named paths out of a copied tree.

Rendered from [`docs/how-to/skip-files-when-copying.md`](https://github.com/jostraca/jostraca/blob/master/docs/how-to/skip-files-when-copying.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.

Two mechanisms, and they do different jobs. `cmp.Copy.ignore` matches **names** anywhere in the tree; `exclude` matches **paths** relative to the copied source root.

The source holds the file worth copying, `tpl/src/app.js`:

```js
export const app = 1
```

an editor backup beside it, `tpl/src/app.js~`:

```text
an editor backup
```

something internal, `tpl/src/notes.md`:

```text
internal notes
```

and a cache directory, `tpl/src/.cache/blob.txt`:

```text
cached
```

```js
import { Jostraca, Project, Copy } from 'jostraca'

const jostraca = Jostraca({
  cmp: { Copy: { ignore: [/^\.cache$/] } },
})

await jostraca.generate({ folder: './out' }, () => {
  Project({}, () => {
    Copy({ from: './tpl/src', exclude: ['notes.md'] })
  })
})
```

```text
app.js
```

Three rules were in play:

-   **`app.js~` went without being asked.** Names ending `~` or `-jostraca-off` are always skipped, whatever you configure. That rule cannot be turned off, and it applies to directories too.
-   **`.cache/` was pruned by `cmp.Copy.ignore`.** The list holds regular expressions matched against the bare entry name, so naming a directory removes its whole subtree.
-   **`notes.md` was dropped by `exclude`.** That one is matched against the path relative to the copied source root, however deep in the output tree the `Copy` sits.

Two traps in `exclude`. String entries are compared exactly, so `'./a.txt'` does **not** match `a.txt`. And a boolean is accepted and does nothing at all: `exclude: true` copies everything.

`cmp.Copy.ignore` merges over the built-in default index by index, so a list of your own replaces the default’s first entry. That costs nothing in practice, because the `~` rule is hard-coded as well.

## See also

-   [Copy a directory into the output](https://jostraca.org/how-to/copy-a-directory).
-   [Options reference](https://jostraca.org/docs/reference-options#options) for `cmp.Copy.ignore`.