This commit is contained in:
Aiden McClelland
2024-06-24 10:43:39 -06:00
3 changed files with 25 additions and 41 deletions

View File

@@ -1,4 +1,4 @@
import { DBCache, PatchOp } from './types' import { Dump, PatchOp } from './types'
export interface BaseOperation { export interface BaseOperation {
path: string path: string
@@ -37,10 +37,10 @@ export function getValueByPointer<T extends Record<string, T>>(
} }
export function applyOperation<T>( export function applyOperation<T>(
doc: DBCache<Record<string, any>>, doc: Dump<Record<string, any>>,
{ path, op, value }: Operation<T> & { value?: T }, { path, op, value }: Operation<T> & { value?: T },
) { ) {
doc.data = recursiveApply(doc.data, arrayFromPath(path), op, value) doc.value = recursiveApply(doc.value, arrayFromPath(path), op, value)
} }
export function arrayFromPath(path: string): string[] { export function arrayFromPath(path: string): string[] {
@@ -61,7 +61,7 @@ export function pathFromArray(args: Array<string | number>): string {
args args
.map(a => .map(a =>
String(a) String(a)
// do not change order, "~" needs to be replaced first // do not change order, "~" needs to be replaced first
.replace(new RegExp('~', 'g'), '~0') .replace(new RegExp('~', 'g'), '~0')
.replace(new RegExp('/', 'g'), '~1'), .replace(new RegExp('/', 'g'), '~1'),
) )

View File

@@ -1,4 +1,4 @@
import { Bootstrapper, DBCache, Dump, Revision, Update } from './types' import { Dump, Revision, Update } from './types'
import { import {
BehaviorSubject, BehaviorSubject,
filter, filter,
@@ -24,24 +24,21 @@ export class PatchDB<T extends { [key: string]: any }> {
} }
} = {} } = {}
readonly cache$ = new BehaviorSubject<DBCache<T>>({ constructor(
sequence: 0, private readonly source$: Observable<Update<T>[]>,
data: {} as T, private readonly cache$ = new BehaviorSubject<Dump<T>>({
}) id: 0,
value: {} as T,
}),
) {}
constructor(private readonly source$: Observable<Update<T>[]>) {} start() {
start(bootstrapper: Bootstrapper<T>) {
if (this.sub) return if (this.sub) return
const initialCache = bootstrapper.init()
this.cache$.next(initialCache)
this.sub = this.source$ this.sub = this.source$
.pipe(withLatestFrom(this.cache$)) .pipe(withLatestFrom(this.cache$))
.subscribe(([updates, cache]) => { .subscribe(([updates, cache]) => {
this.proccessUpdates(updates, cache) this.proccessUpdates(updates, cache)
bootstrapper.update(cache)
}) })
} }
@@ -52,7 +49,7 @@ export class PatchDB<T extends { [key: string]: any }> {
this.watchedNodes = {} this.watchedNodes = {}
this.sub.unsubscribe() this.sub.unsubscribe()
this.sub = null this.sub = null
this.cache$.next({ sequence: 0, data: {} as T }) this.cache$.next({ id: 0, value: {} as T })
} }
watch$(): Observable<T> watch$(): Observable<T>
@@ -131,14 +128,13 @@ export class PatchDB<T extends { [key: string]: any }> {
> >
watch$(...args: (string | number)[]): Observable<any> { watch$(...args: (string | number)[]): Observable<any> {
return this.cache$.pipe( return this.cache$.pipe(
filter(({ sequence }) => !!sequence), filter(({ id }) => !!id),
take(1), take(1),
switchMap(({ data }) => { switchMap(({ value }) => {
const path = pathFromArray(args) const path = pathFromArray(args)
if (!this.watchedNodes[path]) { if (!this.watchedNodes[path]) {
const value = getValueByPointer(data, path)
this.watchedNodes[path] = { this.watchedNodes[path] = {
subject: new BehaviorSubject(value), subject: new BehaviorSubject(getValueByPointer(value, path)),
pathArr: arrayFromPath(path), pathArr: arrayFromPath(path),
} }
} }
@@ -147,21 +143,21 @@ export class PatchDB<T extends { [key: string]: any }> {
) )
} }
proccessUpdates(updates: Update<T>[], cache: DBCache<T>) { proccessUpdates(updates: Update<T>[], cache: Dump<T>) {
updates.forEach(update => { updates.forEach(update => {
if (this.isRevision(update)) { if (this.isRevision(update)) {
const expected = cache.sequence + 1 const expected = cache.id + 1
if (update.id < expected) return if (update.id < expected) return
this.handleRevision(update, cache) this.handleRevision(update, cache)
} else { } else {
this.handleDump(update, cache) this.handleDump(update, cache)
} }
cache.sequence = update.id cache.id = update.id
}) })
this.cache$.next(cache) this.cache$.next(cache)
} }
private handleRevision(revision: Revision, cache: DBCache<T>): void { private handleRevision(revision: Revision, cache: Dump<T>): void {
// apply opperations // apply opperations
revision.patch.forEach(op => { revision.patch.forEach(op => {
applyOperation(cache, op) applyOperation(cache, op)
@@ -172,14 +168,14 @@ export class PatchDB<T extends { [key: string]: any }> {
const arr = arrayFromPath(path) const arr = arrayFromPath(path)
return startsWith(pathArr, arr) || startsWith(arr, pathArr) return startsWith(pathArr, arr) || startsWith(arr, pathArr)
}) })
if (match) this.updateWatchedNode(watchedPath, cache.data) if (match) this.updateWatchedNode(watchedPath, cache.value)
}) })
} }
private handleDump(dump: Dump<T>, cache: DBCache<T>): void { private handleDump(dump: Dump<T>, cache: Dump<T>): void {
cache.data = { ...dump.value } cache.value = { ...dump.value }
Object.keys(this.watchedNodes).forEach(watchedPath => { Object.keys(this.watchedNodes).forEach(watchedPath => {
this.updateWatchedNode(watchedPath, cache.data) this.updateWatchedNode(watchedPath, cache.value)
}) })
} }

View File

@@ -1,12 +1,10 @@
import { Operation } from './json-patch-lib' import { Operation } from './json-patch-lib'
// revise a collection of nodes.
export type Revision = { export type Revision = {
id: number id: number
patch: Operation<unknown>[] patch: Operation<unknown>[]
} }
// dump/replace the entire store with T
export type Dump<T> = { id: number; value: T } export type Dump<T> = { id: number; value: T }
export type Update<T> = Revision | Dump<T> export type Update<T> = Revision | Dump<T>
@@ -16,13 +14,3 @@ export enum PatchOp {
REMOVE = 'remove', REMOVE = 'remove',
REPLACE = 'replace', REPLACE = 'replace',
} }
export interface Bootstrapper<T extends Record<string, any>> {
init(): DBCache<T>
update(cache: DBCache<T>): void
}
export interface DBCache<T extends Record<string, any>> {
sequence: number
data: T
}