yew-fmt

Format HTML-enhanced Rust like normal Rust

yew-fmt is a drop-in replacement for rustfmt, which means that, on top of all of its formatting, it applies formatting to the HTML in yew::html! and yew::html_nested!.

Install yew-fmt

Installing it is as easy as

cargo install yew-fmt

Use yew-fmt in your project

After installing it, it can be used from the command line just like rustfmt. To verify this, run the following command:

yew-fmt --version

However, because it's a drop-in replacement for rustfmt, it can replace the latter to be the backend for the cargo fmt command. To make it the default formatter on your machine, export an environment variable RUSTFMT and set it to yew-fmt, on Linux/MacOS it can be done with the following command:

export RUSTFMT=yew-fmt

Configure yew-fmt

In the fashion of being a drop-in replacement, it inherits methods of configuration from rustfmt, which is explained here, and all of configuration options for rustfmt are also supported by yew-fmt. On top of those, yew-fmt provides the following options of its own:

yew.html_width

Maximum width of an HTML node before falling back to vertical formatting.

• Default value: inherited from max_width
• Possible values: any positive integer

yew.use_small_heuristics

Along with yew.html_width, different kinds of nodes have different rules for when to be broken up. This option controls what set of rules to use.

• Default value: inherited from use_small_heuristics
• Possible values: "Default", "Off", "Max"

Default

Elements are not broken up if they have no children or if all their children are block nodes, otherwise they're broken up.
if nodes are always broken up

<div>
    <code>{ "panic!(" }{ msg }{ ")" }</code>
</div>
if condition {
    <p>{ "Something else" }</p>
}

Max

Elements can only be broken up due to exceeding yew.html_width.
if nodes will remain on 1 line unless they exceed yew.html_width

<div><code>{ "panic!(" }{ msg }{ ")" }</code></div>
if condition { <p>{ "Something else" }</p> }

Off

Elements and if nodes are always broken up

<div>
    <code>
        { "panic!(" }
        { msg }
        { ")" }
    </code>
</div>
if condition {
    <p>
        { "Something else" }
    </p>
}

yew.use_prop_init_shorthand

Use prop initialiser shorthand if possible.

• Default value: inherited from use_field_init_shorthand
• Possible values: true, false

false

<div id={id} />

true

<div {id} />

yew.unwrap_literal_prop_values

Remove braces around prop initialisers if they consist of only a literal.

• Default value: true
• Possible values: true, false

false

<div id={"foo"} class="bar" />

true

<div id="foo" class="bar" />

yew.self_close_elements

Make elements self-closed if they have no children.

• Default value: true
• Possible values: true, false

false

<div id="foo"></div>

true

<div id="foo" />

yew.html_flavor

By default yew-fmt formats the HTML using Yew's original syntax, however, this feature allows for switching the HTML flavor used to accomodate e.g. community-made variations. As of now, the only supported syntactic variation is that of yew-html-ext

• Default value: "Base"
• Possible values: "Base", "Ext"

Base

The default syntax specified by Yew itself.

Ext

The syntax of yew-html-ext.

Keep in mind, work is still in progress

As the project is very early on in development, not all CLI options of rustfmt are supported, yet the eventual target of the project is 100% compatibility, so all the ❌ in the table below will eventually become 🟩.

CLI option	support
--backup	🟩
--check	🟩
--color	🟩
--config	🟩
--config-path	🟩
--edition	🟩
--emit files	🟩
--emit stdout	🟩
--files-with-diff	🟩
--print-config	❌
--verbose	❌
--quiet	🟩