API Reference

RenderJS extends native constructors' .prototype directly (src/prototype/*.ts); nothing is a standalone import. Loading the bundle is enough to make every method below available globally.

String

Source: src/prototype/String.ts

Method / Property	Description
`"selector".RJS(body)`	Starts an `RJS` instance on the matched element; see 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`

Element

Source: src/prototype/Element.ts

Method / Property	Description
`el.length`	`this.children.length`
`el.$i`	Index of the element among its parent's children
`el.$attributes`	All attributes as a plain `{ name: value }` object
`el._(value)` / `el.__(value)`	Append / replace children — strings and numbers become a text node; plain objects are pretty-printed as `<br>`-joined JSON
`el._style(map)` / `el._data(map)` / `el._attr(map)`	Chainable: set multiple `style` / `dataset` / attribute key-values from an object
`el._class(list)`	Chainable: add one or more classes (string, comma/space/dot-separated, or array)
`el.class_(list)` / `el.style_(list)` / `el.data_(list)` / `el.attr_(list)`	Chainable: remove classes / clear styles / delete dataset keys / remove attributes
`el.$style(key)` / `el.$data(key)` / `el.$attr(key)`	Read a single style property / dataset entry / attribute value
`el.class__()`	Chainable: clears `className` entirely
`el.__class(list)`	Chainable: replaces the whole class list
`el.$$class(list)`	`true` only if every class in `list` is present
`el.$$class_(bool, list)`	Chainable: adds `list` when `bool` is falsy, removes it when truthy (or auto-detects current state if `bool` is omitted)
`el.$$data(key, value?)` / `el.$$attr(key, value?)`	`true` if the dataset/attribute value equals `value`, or is non-empty when `value` is omitted
`el._children(...args)`	Chainable: appends each argument via `_child`
`el._child(value, before)`	Chainable: append/insert a child (or array of children) by index or reference `Element`
`el.__child(value)`	Chainable: replaces children (`replaceChildren`)
`el.$child(value)`	Query a descendant by a mixed array of selector strings and numeric indices
`el.$parent(count)` / `el.$pre(count)` / `el.$next(count)`	Walk `count` steps up `parentElement` / `previousElementSibling` / `nextElementSibling`
`el.$sel(selector)` / `el.$selAll(selector)`	`querySelector` / `querySelectorAll` guarded against an empty selector
`el._click(fn)` (and every DOM event name, e.g. `_input`, `_keydown`, `_touchstart`, `_drop`, ...)	Chainable `on<event> = fn` assignment

Array

Source: src/prototype/Array.ts

Method / Property	Description
`arr.$sum`	Sum of a numeric array via `reduce`
`arr.$shuffle`	In-place Fisher–Yates shuffle; returns `this`
`arr.$map`	A `Map` of `value → index` for every entry
`arr._(value, index?)`	Negative-index-aware insert (`splice`); appends when `index` is omitted
`arr.$(index)`	Negative-index-aware read
`arr.$i(target)`	`indexOf(target)`, returning `undefined` instead of `-1`
`arr.$_(index)`	Negative-index-aware removal (`splice`)
`arr.$$(target?)`	`true` if non-empty (no argument) or if `target` is present
`arr.$req(body)`	Joins the array as `/`-separated URL path segments, then calls `$req` on the resulting path

Object

Source: src/prototype/Object.ts (extends Object.prototype, so these apply to plain objects)

Method / Property	Description
`obj.length`	`Object.keys(this).length`
`obj.$keys` / `obj.$values`	`Object.keys(this)` / `Object.values(this)`
`obj.$map`	Own enumerable entries as a `Map`
`obj.forEach(cb)`	Array-like iteration: `cb(key, value)` over own enumerable properties
`obj._(key, value, replace = true)`	Conditional setter — only overwrites an existing key when `replace` is `true`
`obj.$$(key?)`	`hasOwnProperty(key)` if `key` given, else `this.length > 0`

URL

Source: src/prototype/URL.ts

Method / Property	Description
`url.$queryAll`	Query string parsed into a plain object
`url.$image`	Promise resolving a preloaded `Image` for the URL
`url.$$200(isImg = false)`	Fetches the URL; if the response is an image, converts it to an object-URL blob (`{ src, img }`) unless it's SVG and `isImg` is falsy
`url.$req(body, once = false)`	Fetch wrapper: JSON or `FormData` body (via `body.json`/`body.files`/`body.tag`), custom `header`/`credentials`, request de-duplication through a shared `Map` keyed by URL, automatic JSON/text response parsing, rejects with response text on 4xx/5xx
`url.$$query(key)`	`searchParams.get(key)`
`url._history(title?)`	`pushState` to this URL, records it in the in-memory history stack, optionally sets `document.title`
`url._query(obj)`	Returns a new `URL` with `obj`'s keys merged into the existing query string
`url.__history(title?)`	`replaceState` to this URL (also updates the history stack)
`url.__query(obj)`	Returns a new `URL` with the query string replaced entirely by `obj`
`url.query_(keys)`	Returns a new `URL` with the given key (or array of keys) removed from the query string
`url.query__()`	Returns a new `URL` with the query string cleared

window

Source: src/prototype/window.ts

Method	Description
`_Listener(target?)`	With no argument, enables both the lazyload and SVG observers. With an argument, `target.svg` gates the lazyload observer and `target.lazyload` gates the SVG observer (see Listener System for the observer internals)
`$file(file)`	Wraps a `File`/`Blob` in a `FileReader.readAsDataURL`, resolving with the `load` event
`$cookie(key)`	Reads and URI-decodes a cookie; JSON-parses the value automatically if it looks like JSON
`_cookie(key, body, expire = 3600)`	Writes a cookie (`expire` in seconds); objects are `JSON.stringify`'d first
`$(selector)`	Module-level shortcut for `"selector".$`
`$all(selector)`	Module-level shortcut for `"selector".$all`
`_child(value, before)` / `__child(value)`	Append to / replace the children of `document.body`

Date

Source: src/prototype/Date.ts

Method / Property	Description
`date.$y` / `$yy` / `$yyyy`	Year (raw, 2-digit, 4-digit)
`date.$M` / `$MM`	Month, 1-indexed (raw, zero-padded)
`date.$D` / `$DD`	Day of month (raw, zero-padded)
`date.$d` / `$dd` / `$ddd` / `$dddd`	Day of week: index, then localized name at increasing length (English abbreviations or 星期X in `zh` locales, detected via `navigator.language`)
`date.$H` / `$HH`	24-hour hour (raw, zero-padded)
`date.$h` / `$hh`	12-hour hour (raw, zero-padded)
`date.$a` / `$A`	`am`/`pm` (lower/upper case)
`date.$m` / `$mm`	Minutes (raw, zero-padded)
`date.$s` / `$ss`	Seconds (raw, zero-padded)
`date.$S` / `$SS` / `$SSS`	Milliseconds, sliced to 1/2/3 digits
`date.$timestamp`	Unix timestamp in seconds
`date.$gone`	Humanized relative time (`"3 days"` / `"3天"`, `"Coming in..."` / `"還有..."`, `"recent"` / `"剛剛"` for < 1 minute), localized by `navigator.language`
`date.$format(format = "yyyy/MM/DD (ddd) HH:mm:ss")`	Token-based formatter; supports `Y`/`M`/`D`/`H`/`h`/`m`/`s`/`S`/`A`/`a`/`d` tokens at the repeat-counts shown above
`date.$date(body?)`	Given `{ start }` / `{ end }` / `{ pre: { start } }` / `{ pre: { end } }`, returns the first/last day of the current or previous month; otherwise `new Date()`

Number

Source: src/prototype/Number.ts

Method / Property	Description
`n.$uniKey`	Random string of length `n`, drawn from a 52-character alphabet, deduplicated against previously generated keys for the process lifetime
`n.$ASCII`	`String.fromCharCode(n)`
`n.$date`	Treats `n` as a Unix timestamp (seconds) and returns the corresponding `Date`
`n.$y` / `$M` / `$D` / `$d` / `$H` / `$h` / `$a` / `$A` / `$m` / `$s` / `$S` (and their padded/repeated variants) / `$gone`	Forwarded to `n.$date`'s equivalent `Date` getter
`n.$format(format)`	Forwarded to `n.$date.$format(format)`

Map

Source: src/prototype/Map.ts

Method / Property	Description
`map.length`	`this.size`
`map.$keys` / `map.$values`	Iterators over keys / values
`map.$json`	`Object.fromEntries(this)`
`map._(key, value?)`	Chainable `set(key, value)`
`map.$(key?)`	`get(key)`
`map.$_(key?)`	Chainable `delete(key)`
`map.$$(key?)`	`has(key)` if given, else `this.size > 0`

Image

Source: src/prototype/Image.ts

Method / Property	Description
`img.copy(mime = "image/jpeg")`	Async; copies the image to the clipboard via `ClipboardItem`
`img.download(mime = "image/jpeg", filename?)`	Triggers a browser download using an object-URL `<a download>` link
`img.$base64(mime, size?)`	Re-encodes via an offscreen `<canvas>`; `size` (if smaller than the longest side) proportionally downscales the image first
`img.$blob(mime, size?)`	`$base64` decoded back into a `Blob`

HTMLElement

Source: src/prototype/HTMLElement.ts

Method / Property	Description
`el._display(value)`	Chainable `style.display = value`
`el.width(v)` / `height(v)` / `paddingTop(v)` / `paddingLeft(v)` / `paddingBottom(v)` / `paddingRight(v)` / `marginTop(v)` / `marginLeft(v)` / `marginBottom(v)` / `marginRight(v)`	Chainable numeric style setters; a bare number/numeric-string gets `px` appended automatically
`el.padding(top, right?, bottom?, left?)` / `el.margin(...)`	CSS-shorthand-style chainable setter (1–4 args, same fallback rules as the `padding`/`margin` CSS property)
`el.scrollToX(value, animation?)` / `el.scrollToY(value, animation?)`	Scrolls to an absolute offset (clamped to content bounds), optionally with `behavior: "smooth"`
`el.scrollToT(animation?)` / `el.scrollToB(animation?)`	Scroll to the top / bottom edge
`el.scrollToL(animation?)` / `el.scrollToR(animation?)`	Scroll to the left / right edge

File

Source: src/prototype/File.ts

Method	Description
`file.$image(isVideo = false)`	Returns a `Promise<HTMLImageElement>`. For images, decodes via `FileReader.readAsDataURL`. For video files (`isVideo: true`), loads the file into an offscreen `<video>`, seeks to the first decoded frame, and captures it onto a `<canvas>` to produce a JPEG thumbnail

HTMLVideoElement

Source: src/prototype/HTMLVideoElement.ts

Method	Description
`video._config({ preload, loop, muted, controls, playsinline, download, remote })`	Chainable one-call setup: always disables the native download/remote-playback UI via `controlsList`, then applies each provided flag (`download: false`/`remote: false` re-add the corresponding `controlsList` token)

HTMLFormElement

Source: src/prototype/HTMLFormElement.ts

Method / Property	Description
`form.$map`	Form fields as a `Map` (via an internal `FormData` wrapper)
`form.$json`	Form fields as a plain object

HTMLLinkElement

Source: src/prototype/HTMLLinkElement.ts

Method	Description
`a._go(href?)`	Chainable: sets `href` (if given) and navigates in the current tab (`target = "_self"`)
`a._open(href?)`	Chainable: sets `href` (if given) and navigates in a new tab (`target = "_blank"`)

FormData

Source: src/prototype/FormData.ts

Method / Property	Description
`formData.$map`	Entries as a `Map`
`formData.$json`	Entries as a plain object

DocumentFragment

Source: src/prototype/DocumentFragment.ts

Method / Property	Description
`fragment.innerHTML`	Serializes the fragment's contents via a detached `<div>`
`fragment.length`	`this.children.length`
`fragment._children(...args)`	Appends each argument as a child
`fragment._child(value)`	Appends a value (or array of values); strings/numbers become text nodes