feat: add support for launching with an initial state

changelog.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - add `beforeLaunch` and `onLaunch` parameters to allow us to hook into the launching process
 - add `getBrowserFS` method for accessing the corresponding `BFSEmscriptenFS` object of the emulator
 - add a new method `sendCommand` for sending commands to RetroArch
+- add support for launching with an initial state
 
 ## [0.8.1](https://github.com/arianrhodsandlot/nostalgist/compare/v0.8.0...v0.8.1) - 2024-02-24
 

demo/demo.ts

@@ -4,7 +4,7 @@ let nostalgist: Nostalgist
 let state: Awaited<ReturnType<Nostalgist['saveState']>>
 
 async function nes() {
- nostalgist = await Nostalgist.nes('flappybird.nes')
+ nostalgist = await Nostalgist.nes({ rom: 'flappybird.nes' })
 }
 
 async function megadrive() {
@@ -129,6 +129,7 @@ document.body.addEventListener('click', async function listener({ target }) {
  await handler()
  target.blur()
  }
+ Object.assign(window, { nostalgist })
 })
 
 // @ts-expect-error debug code

src/emulator.ts

@@ -48,13 +48,17 @@ export class Emulator {
  return fileName.slice(0, fileName.lastIndexOf('.'))
  }
 
- private get stateFileName() {
+ private get stateFileDirectory() {
  const { core } = this.options
  const coreFullName = coreInfoMap[core.name].corename
  if (!coreFullName) {
  throw new Error(`invalid core name: ${core.name}`)
  }
- return join(raUserdataDir, 'states', coreFullName, `${this.romBaseName}.state`)
+ return join(raUserdataDir, 'states', coreFullName)
+ }
+
+ private get stateFileName() {
+ return join(this.stateFileDirectory, `${this.romBaseName}.state`)
  }
 
  private get stateThumbnailFileName() {
@@ -278,7 +282,7 @@ export class Emulator {
  private async setupFileSystem() {
  const { Module } = this.getEmscripten()
  const { FS, PATH, ERRNO_CODES } = Module
- const { rom, bios } = this.options
+ const { rom, bios, state } = this.options
 
  const browserFS = createEmscriptenFS({ FS, PATH, ERRNO_CODES })
  this.browserFS = browserFS
@@ -290,6 +294,9 @@ export class Emulator {
  if (bios.length > 0) {
  FS.mkdirTree(raSystemDir)
  }
+ if (state) {
+ FS.mkdirTree(this.stateFileDirectory)
+ }
 
  // a hack used for waiting for wasm's instantiation.
  // it's dirty but it works
@@ -302,10 +309,21 @@ export class Emulator {
  waitTime += 5
  }
 
- await Promise.all([
+ const filePromises: Promise<void>[] = []
+ filePromises.push(
  ...rom.map((file) => this.writeBlobToDirectory({ ...file, directory: raContentDir })),
  ...bios.map((file) => this.writeBlobToDirectory({ ...file, directory: raSystemDir })),
- ])
+ )
+ if (state) {
+ const statePromise = this.writeBlobToDirectory({
+ fileName: `${this.romBaseName}.state.auto`,
+ fileContent: state,
+ directory: this.stateFileDirectory,
+ })
+ filePromises.push(statePromise)
+ }
+ await Promise.all(filePromises)
+
  this.checkIsAborted()
  }
 
@@ -393,11 +411,13 @@ export class Emulator {
  private runMain() {
  this.checkIsAborted()
  const { Module } = this.getEmscripten()
- const raArgs: string[] = []
- const { rom } = this.options
- if (rom.length > 0) {
- const [{ fileName }] = rom
- raArgs.push(join(raContentDir, fileName))
+ const { arguments: raArgs = [] } = Module
+ if (!Module.arguments) {
+ const { rom } = this.options
+ if (rom.length > 0) {
+ const [{ fileName }] = rom
+ raArgs.push(join(raContentDir, fileName))
+ }
  }
 
  Module.callMain(raArgs)

src/nostalgist.ts

@@ -458,6 +458,7 @@ export class Nostalgist {
  const {
  size = 'auto',
  respondToGlobalEvents = true,
+ state,
  waitForInteraction,
  signal,
  beforeLaunch,
@@ -485,6 +486,7 @@ export class Nostalgist {
  rom,
  bios,
  shader,
+ state,
  respondToGlobalEvents,
  retroarchConfig,
  retroarchCoreConfig,

src/options.ts

@@ -5,6 +5,7 @@ import { isAbsoluteUrl, path } from './utils'
 const defaultRetroarchConfig: RetroArchConfig = {
  menu_driver: 'rgui',
  notification_show_when_menu_is_alive: true,
+ savestate_auto_load: true,
  savestate_thumbnail_enable: true,
  stdin_cmd_enable: true,
  video_shader_enable: true,

src/types/emulator-options.ts

@@ -28,6 +28,7 @@ export interface EmulatorOptions {
  rom: { fileName: string; fileContent: Blob }[]
  bios: { fileName: string; fileContent: Blob }[]
  shader: { fileName: string; fileContent: Blob }[]
+ state?: Blob | undefined
 
  respondToGlobalEvents: boolean
 

src/types/nostalgist-options.ts

@@ -144,6 +144,8 @@ export interface NostalgistOptions {
  */
  bios?: NostalgistOptionsFiles
 
+ state?: Blob
+
  respondToGlobalEvents?: boolean
 
  /**

src/types/retroarch-config/skeleton.ts

@@ -13,8 +13,8 @@ export interface RetroArchSkeletonConfig {
  * The path is $SRAM_PATH.auto.
  * RetroArch will automatically load any savestate with this path on startup if savestate_auto_load is set.
  */
- savestate_auto_save: string
- savestate_auto_load: string
+ savestate_auto_save: boolean
+ savestate_auto_load: boolean
 
  /**
  * Path to a libretro implementation.

src/utils.ts

@@ -112,17 +112,22 @@ function isPrimitive(obj: unknown) {
  return primitevTypes.includes(type)
 }
 
+function isPlainObject(obj: any) {
+ const { constructor } = obj
+ return constructor === Object || !constructor
+}
+
 function mergeSourceToTarget(target: any, source: any) {
  for (const key in source) {
  if (Object.prototype.hasOwnProperty.call(source, key)) {
  const targetValue = target[key]
  const sourceValue = source[key]
- if (isPrimitive(sourceValue)) {
+ if (isPrimitive(sourceValue) || !isPlainObject(sourceValue)) {
  target[key] = sourceValue
  } else if (Array.isArray(targetValue) && Array.isArray(sourceValue)) {
  target[key] = [...targetValue, ...sourceValue]
  } else {
- target[key] = isPrimitive(targetValue) ? {} : target[key]
+ target[key] = isPrimitive(targetValue) || !isPlainObject(targetValue) ? {} : target[key]
  merge(target[key], sourceValue)
  }
  }