# String Extensions

Methods and getters RenderJS adds to `String.prototype`: DOM construction from tag-selector strings, element queries, JSON and HTML helpers, and URL shortcuts.

## String

Source: `src/prototype/String.ts`

| Method / Property | Description |
| --- | --- |
| `"selector".RJS(body)` | Starts an `RJS` instance on the matched element; see [Core Concepts](/core-concepts) |
| `"tag.class#id"._(attrs, children)` | Builds a real DOM element from a tag-selector string (SVG namespace detection, `input`/`textarea` type/placeholder parsing, `lazyload` attribute wiring) |
| `"selector".$` | Single matching element (`getElementById` for `#id`, otherwise `querySelector`) |
| `"selector".$all` | Array of all matching elements (`[...querySelectorAll(...)]`) |
| `"icon-a icon-b"._fa` | Getter that builds `"i.icon-a.icon-b"._()` — a Font Awesome `<i>` element from space-separated class names |
| `"str".$json` | Safe `JSON.parse(this)`; returns `undefined` (and logs) on parse failure |
| `"str".$$json` | `true` when `$json` did not fail |
| `"str".$html` | HTML-escapes ` `, `<`, `>`, `"`, `'` |
| `"str".copy()` | Async; writes the string to the clipboard via `navigator.clipboard.writeText` |
| `"str".$regexp(flags?, force?)` | Builds a `RegExp` from the string; `force: true` escapes regex metacharacters first |
| `"str".$base64(mimeType)` | Decodes a base64-encoded string into a `Blob` |
| `"str".$$(filter?)` | `RegExp` test, exact-string match, or (no argument) non-empty-after-trim check |
| `"url".$url` | `new URL(this)`, falling back to `new URL(location.origin + this)` for relative paths |
| `"url".$queryAll` | Query string parsed into a plain object (via `$url.$queryAll`) |
| `"url".$img` / `$$200(isImg)` / `$req(body, once)` / `$query` / `_history(title)` / `_query(obj)` / `__history(title)` / `__query(obj)` / `query_(keys)` / `query__()` | Forwarded to the equivalent `URL` method/getter below, applied to `this.$url` |