From d0431c7f81e20dfb77a6fe154292d6b06f433984 Mon Sep 17 00:00:00 2001 From: Joris Date: Tue, 7 Feb 2023 18:38:44 +0100 Subject: Init version --- src/rx.ts | 398 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 398 insertions(+) create mode 100644 src/rx.ts (limited to 'src/rx.ts') diff --git a/src/rx.ts b/src/rx.ts new file mode 100644 index 0000000..dbdd3ad --- /dev/null +++ b/src/rx.ts @@ -0,0 +1,398 @@ +// Html + +export interface Html { + type: 'Tag' | 'WithVar' +} + +export interface Tag extends Html { + type: 'Tag' + tagName: string + attributes: Attributes + children?: Array + onmount?: (element: Element) => void + onunmount?: (element: Element) => void +} + +export interface WithVar extends Html { + type: 'WithVar' + init: A + getChildren: (v: Var, update: (f: (value: A) => A) => void) => Child +} + +interface Attributes { + [key: string]: Rx | AttributeValue +} + +export type AttributeValue + = string + | number + | boolean + | ((event: Event) => void) + | ((element: Element) => void) + +export type Child = false | undefined | string | number | Html | Rx | Array + +function isChild(x: any): x is Child { + return (typeof x === 'string' + || typeof x === 'number' + || isHtml(x) + || isRx(x) + || Array.isArray(x)) +} + +type ValueOrArray = T | Array> + +export function h( + tagName: string, + x?: Attributes | Child, + ...children: Array +): Tag { + if (x === undefined || x === false) { + return { + type: 'Tag', + tagName, + attributes: {} + } + } else if (isChild(x)) { + return { + type: 'Tag', + tagName, + attributes: {}, + children: [x, ...children], + } + } else { + let attributes = x as Attributes + let onmount, onunmount + if ('onmount' in attributes) { + onmount = attributes['onmount'] as (element: Element) => void + delete attributes['onmount'] + } + if ('onunmount' in attributes) { + onunmount = attributes['onunmount'] as (element: Element) => void + delete attributes['onunmount'] + } + return { + type: 'Tag', + tagName, + attributes, + children, + onmount, + onunmount + } + } +} + +export function withVar(init: A, getChildren: (v: Var, update: (f: (value: A) => A) => void) => Child): WithVar { + return { + type: 'WithVar', + init, + getChildren + } +} + +// Rx + +export type RxAble = Rx | A + +export class Rx { + map(f: (value: A) => B): Rx { + return new Map(this, f) + } + + flatMap(f: (value: A) => Rx): Rx { + return new FlatMap(this, f) + } +} + +class Var extends Rx { + readonly type: 'Var' + readonly id: string + + constructor(id: string) { + super() + this.id = id + this.type = 'Var' + } +} + +export class Map extends Rx { + readonly type: 'Map' + readonly rx: Rx + readonly f: (value: A) => B + + constructor(rx: Rx, f: (value: A) => B) { + super() + this.type = 'Map' + this.rx = rx + this.f = f + } +} + +export class FlatMap extends Rx { + readonly type: 'FlatMap' + readonly rx: Rx + readonly f: (value: A) => Rx + + constructor(rx: Rx, f: (value: A) => Rx) { + super() + this.type = 'FlatMap' + this.rx = rx + this.f = f + } +} + +// Mount + +export function mount(child: Child): Cancelable { + const state = new State() + let appendRes = appendChild(state, document.body, child) + return appendRes.cancel +} + +interface StateEntry { + value: A + subscribers: Array<(value: A) => void> +} + +class State { + readonly state: {[key: string]: StateEntry} + varCounter: bigint + + constructor() { + this.state = {} + this.varCounter = BigInt(0) + } + + register(initValue: A) { + const v = new Var(this.varCounter.toString()) + this.varCounter += BigInt(1) + this.state[v.id] = { + value: initValue, + subscribers: [] + } + return v + } + + unregister(v: Var) { + delete this.state[v.id] + } + + get(v: Var) { + return this.state[v.id].value + } + + update(v: Var, f: (value: A) => A) { + const value = f(this.state[v.id].value) + this.state[v.id].value = value + this.state[v.id].subscribers.forEach(notify => { + // Don’t notify if it has been removed from a precedent notifier + if (this.state[v.id].subscribers.indexOf(notify) !== -1) { + notify(value) + } + }) + } + + subscribe(v: Var, notify: (value: A) => void): Cancelable { + this.state[v.id].subscribers.push(notify) + return () => this.state[v.id].subscribers = this.state[v.id].subscribers.filter(n => n !== notify) + } +} + +// Cancelable + +type Cancelable = () => void + +const voidCancel = () => {} + +// Removable + +type Removable = () => void + +const voidRemove = () => {} + +// Rx run + +function rxRun(state: State, rx: Rx, effect: (value: A) => void): Cancelable { + if (isVar(rx)) { + const cancel = state.subscribe(rx, effect) + effect(state.get(rx)) + return cancel + } else if (isMap(rx)) { + return rxRun(state, rx.rx, value => effect(rx.f(value))) + } else if (isFlatMap(rx)) { + let cancel1 = voidCancel + const cancel2 = rxRun(state, rx.rx, (value: A) => { + cancel1() + cancel1 = rxRun(state, rx.f(value), effect) + }) + return () => { + cancel2() + cancel1() + } + } else { + throw new Error(`Unrecognized rx: ${rx}`) + } +} + +function isRx(x: any): x is Rx { + return x !== undefined && x.type !== undefined && (x.type === "Var" || x.type === "Map" || x.type === "FlatMap") +} + +function isVar(x: any): x is Var { + return x.type === "Var" +} + +function isMap(x: any): x is Map { + return x.type === "Map" +} + +function isFlatMap(x: any): x is FlatMap { + return x.type === "FlatMap" +} + +// Append + +interface AppendResult { + cancel: Cancelable + remove: Removable + lastAdded?: Node +} + +function appendChild(state: State, element: Element, child: Child, lastAdded?: Node): AppendResult { + if (Array.isArray(child)) { + let cancels: Array = [] + let removes: Array = [] + child.forEach((o) => { + const appendResult = appendChild(state, element, o, lastAdded) + cancels.push(appendResult.cancel) + removes.push(appendResult.remove) + lastAdded = appendResult.lastAdded + }) + return { + cancel: () => cancels.forEach((o) => o()), + remove: () => removes.forEach((o) => o()), + lastAdded + } + } else if (typeof child == "string") { + const node = document.createTextNode(child) + appendNode(element, node, lastAdded) + return { + cancel: voidCancel, + remove: () => element.removeChild(node), + lastAdded: node + } + } else if (typeof child == "number") { + return appendChild(state, element, child.toString(), lastAdded) + } else if (isTag(child)) { + const { tagName, attributes, children, onmount, onunmount } = child + + const childElement = document.createElement(tagName) + const cancelAttributes = Object.entries(attributes).map(([key, value]) => { + if (isRx(value)) { + return rxRun(state, value, newValue => setAttribute(state, childElement, key, newValue)) + } else { + setAttribute(state, childElement, key, value) + } + }) + + const appendChildrenRes = appendChild(state, childElement, children) + + appendNode(element, childElement, lastAdded) + + if (onmount !== undefined) { + onmount(childElement) + } + + return { + cancel: () => { + cancelAttributes.forEach(cancel => cancel !== undefined ? cancel() : {}) + appendChildrenRes.cancel() + if (onunmount !== undefined) { + onunmount(childElement) + } + }, + remove: () => element.removeChild(childElement), + lastAdded: childElement, + } + } else if (isWithVar(child)) { + const { init, getChildren } = child + const v = state.register(init) + const children = getChildren(v, f => state.update(v, f)) + const appendRes = appendChild(state, element, children) + return { + cancel: () => { + appendRes.cancel() + state.unregister(v) + }, + remove: () => appendRes.remove(), + lastAdded: appendRes.lastAdded + } + } else if (isRx(child)) { + const rxBase = document.createTextNode("") + element.append(rxBase) + let appendRes: AppendResult = { + cancel: voidCancel, + remove: voidRemove, + lastAdded: rxBase + } + const cancelRx = rxRun(state, child, (value: Child) => { + appendRes.cancel() + appendRes.remove() + appendRes = appendChild(state, element, value, rxBase) + }) + return { + cancel: () => { + appendRes.cancel() + cancelRx() + }, + remove: appendRes.remove, + lastAdded: appendRes.lastAdded, + } + } else if (child === undefined || child === false) { + return { + cancel: voidCancel, + remove: voidRemove, + lastAdded + } + } else { + throw new Error(`Unrecognized child: ${child}`) + } +} + +function isHtml(x: any): x is Html { + return isTag(x) || isWithVar(x) +} + +function isTag(x: any): x is Tag { + return x !== undefined && x.type === "Tag" +} + +function isWithVar(x: any): x is WithVar { + return x !== undefined && x.type === "WithVar" +} + +function appendNode(base: Element, node: Node, lastAdded?: Node) { + if (lastAdded !== undefined) { + base.insertBefore(node, lastAdded.nextSibling) + } else { + base.append(node) + } +} + +function setAttribute(state: State, element: Element, key: string, attribute: AttributeValue) { + if (typeof attribute == "boolean") { + if (attribute) { + // @ts-ignore + element[key] = "true" + } + } else if (typeof attribute == "number") { + // @ts-ignore + element[key] = attribute.toString() + } else if (typeof attribute == "string") { + // @ts-ignore + element[key] = attribute + } else { + // @ts-ignore + element[key] = (event: Event) => attribute(event) + } +} -- cgit v1.2.3