# `IgniterCss.Transform`
[🔗](https://github.com/ash-project/igniter_css/blob/v1.1.2/lib/igniter_css/transform.ex#L5)

Whole-file transforms. **These are not codemods.**

Everything in `IgniterCss` is diff-minimal by construction. The functions here
deliberately are not: minifying and beautifying rewrite every byte, and
minifying discards comments, because that is what minifying *is*.

Use them for build-time output and reporting. Do not use them to patch a
user's stylesheet — `IgniterCss.set_declaration/5` and friends exist for that,
and they never route their output through here.

# `opts`

```elixir
@type opts() :: keyword()
```

# `beautify`

```elixir
@spec beautify(String.t(), opts()) :: {:ok, String.t()} | {:error, String.t()}
```

Re-print the stylesheet with one declaration per line and consistent
indentation, keeping every comment.

    iex> IgniterCss.Transform.beautify(".a{color:red;margin:0}")
    {:ok, ".a {\n  color: red;\n  margin: 0;\n}\n"}

# `merge_stylesheets`

```elixir
@spec merge_stylesheets([String.t()], opts()) ::
  {:ok, String.t()} | {:error, String.t()}
```

Concatenate stylesheets, then drop rules a later copy makes redundant.

A rule is dropped only when a later one has the same selector **and** a
byte-identical body, so an intentional override survives.

    iex> IgniterCss.Transform.merge_stylesheets([".a { color: red; }", ".a { color: red; }"])
    {:ok, ".a { color: red; }\n"}

# `minify`

```elixir
@spec minify(String.t(), opts()) :: {:ok, String.t()} | {:error, String.t()}
```

Strip comments and collapse whitespace.

Driven by the token stream rather than by text matching, so a `;` inside
`url(...)` or a `/*` inside a string is never mistaken for syntax. Whitespace
is kept only where removing it would change how the result tokenises, so
`@media screen and (min-width: 40em)` keeps the space after `and`.

    iex> IgniterCss.Transform.minify(".a {\n  color: red;\n}\n")
    {:ok, ".a{color:red}"}

---

*Consult [api-reference.md](api-reference.md) for complete listing*