# Summit.start

> Start Summit and initialize the DOM.

`Summit.start` scans the DOM, brings every `s-` attribute to life, and begins
watching for elements added later. The script-tag build calls it for you. The
npm build leaves the timing to you, so you can register your data, directives,
and magics first.

## Starting

Call `Summit.start()` to initialize the whole document, or pass a root element to
initialize just that subtree:

```js
Summit.start();
```

```js
Summit.start(document.getElementById("app"));
```

When no root is given, Summit starts from `document.body`. After the initial
pass it keeps a watcher on the document, so any `s-` markup you add later comes
alive on its own and torn-down elements are cleaned up.

## It runs once

`Summit.start` is idempotent. The first call initializes the DOM; later calls
return immediately and do nothing. That makes it safe to call after registering
features without worrying about double-initialization:

```js
Summit.directive("sparkle", (el) => {
  el.style.transition = "opacity .3s";
});
Summit.start();
```

The script-tag build already calls `start()` once the DOM is ready, so calling
it again yourself is harmless.

## Lifecycle events

`start` dispatches two events on `document`, so you can hook into
initialization:

- `summit:init` fires just before Summit walks the DOM.
- `summit:initialized` fires after the initial pass completes.

```js
document.addEventListener("summit:initialized", () => {
  console.log("Summit is running");
});
```

## Checking status and version

`Summit.started()` returns `true` once `start` has run, and `false` before:

```js
if (!Summit.started()) Summit.start();
```

`Summit.version` is the version string of the running build, the same as the
`version` in the package's package.json:

```js
console.log(Summit.version); // "1.0.0"
```

In every npm release up to and including 0.4.3, `Summit.version` reads
`"0.1.0"` whatever the real version is. The fix was in 0.4.4, which was released
on GitHub only, so on npm it starts with 1.0.0. On 0.4.3 or older, read the
package's package.json if you need the installed version.

For install options and manual-start setup, see
[Installation](https://summitjs.velofy.co/installation/).