First commit, basic tests/docs

Author: JAForbes

.github/workflows/test.yml

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+name: Test
+
+on:
+  push:
+
+jobs:
+  test:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [20.x]
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v3
+      with:
+        node-version: ${{ matrix.node-version }}
+        cache: 'npm'
+    - run: npm ci
+    - run: npm test

.gitignore

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+node_modules/*
+logs
+dist
+coverage
+*output*

.prettierrc

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+{
+    "useTabs": true,
+    "semi": false,
+    "singleQuote": true,
+    "embeddedLanguageFormatting": "auto"
+}

.vscode/launch.json

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+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "test",
+            "type": "node",
+            "request": "launch",
+            "args": [
+                "--test",
+                "${relativeFile}"
+            ],
+            "runtimeArgs": [
+                "--import",
+                "tsx"
+            ],
+            "cwd": "${workspaceRoot}",
+            "protocol": "inspector",
+            "internalConsoleOptions": "openOnSessionStart"
+        }
+    ]
+}

.vscode/settings.json

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+{
+    "javascript.format.enable": false,
+    "typescript.format.enable": false
+}

lib/index.ts

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+export type Window = typeof window
+export type Location = typeof window.location
+export type History = typeof window.history
+
+export type State = { path?: string }
+
+export type OnChange = (state: State) => void
+
+interface InternalInstance {
+	back(): void
+	go(path: string, options?: { replace: boolean }): void
+	onChange: OnChange
+	get(): State
+	end(): void
+	prefix: () => string
+	child(options: { prefix: string; onChange?: OnChange }): InternalInstance
+}
+
+interface Attrs {
+	_window?: Window
+	onChange?: (s: State) => any
+}
+
+interface ChildAttrs {
+	_window: Window
+	prefix: string
+	onChange: OnChange
+	children: Set<InternalInstance>
+	reportChanges(): void
+}
+
+function normalizePath(str: string): string {
+	if (str == '' || str == '/') {
+		return '/'
+	} else if (str.at(-1) == '/') {
+		return str.slice(0, -1)
+	} else {
+		return str
+	}
+}
+
+function Superhistory({
+	_window = globalThis.window,
+	onChange = () => {},
+}: Attrs = {}): InternalInstance {
+	const children = new Set<InternalInstance>()
+
+	const reportChanges = () => {
+		onChange({
+			path: _window.location.pathname,
+		})
+		for (let child of children) {
+			child?.onChange?.(child.get())
+		}
+	}
+	const onpopstate = () => {
+		reportChanges()
+	}
+
+	_window.addEventListener('popstate', onpopstate)
+
+	function go(path: string, options: { replace?: boolean } = {}) {
+		path = normalizePath(path)
+		_window.history[`${options.replace ? 'replace' : 'push'}State`](
+			null,
+			'',
+			path,
+		)
+		onChange({
+			path,
+		})
+	}
+
+	function back() {
+		_window.history.back()
+	}
+
+	function end() {
+		_window.removeEventListener('popstate', onpopstate)
+	}
+
+	function get() {
+		return { path: normalizePath(_window.location.pathname) }
+	}
+
+	function prefix() {
+		return '/'
+	}
+
+	function child({
+		prefix = '',
+		onChange,
+	}: {
+		prefix: string
+		onChange: OnChange
+	}) {
+		const child = SuperhistoryChild({
+			_window,
+			prefix,
+			onChange,
+			children,
+			reportChanges,
+		})
+		children.add(child)
+		return child
+	}
+
+	return { go, end, back, get, prefix, child, onChange }
+}
+
+function SuperhistoryChild({
+	_window,
+	prefix: _prefix,
+	onChange,
+	children: parentChildren,
+	reportChanges,
+}: ChildAttrs): InternalInstance {
+	_prefix = normalizePath(_prefix)
+
+	const children = new Set<InternalInstance>()
+	function back() {
+		_window.history.back()
+	}
+
+	function end() {
+		// delete from the root list
+		parentChildren.delete(self)
+
+		// loop through our list to let other child delete
+		// from the root list
+		// our list will gc on its own when it is de-referenced
+		for( let child of children ) {
+			child.end()
+		}
+	}
+
+	function go(path: string, options: { replace?: boolean } = {}) {
+		path = normalizePath(path)
+		_window.history[`${options.replace ? 'replace' : 'push'}State`](
+			null,
+			'',
+			normalizePath(_prefix) + normalizePath(path),
+		)
+		reportChanges()
+	}
+
+	function get() {
+		const rootPath = _window.location.pathname
+		if (!_prefix) {
+			return { path: rootPath }
+		}
+		const [_, child] = rootPath.split(_prefix)
+		return { path: child != null ? normalizePath(child) : child }
+	}
+
+	function prefix() {
+		return _prefix
+	}
+
+	function child({
+		prefix = '',
+		onChange,
+	}: {
+		prefix: string
+		onChange: OnChange
+	}) {
+		const child = SuperhistoryChild({
+			_window,
+			prefix: _prefix + prefix,
+			onChange,
+			children: parentChildren,
+			reportChanges,
+		})
+		parentChildren.add(child)
+		return child
+	}
+
+	const self = { go, end, back, get, prefix, child, onChange }
+	return self
+}
+
+export default Superhistory