fix: update build and plugin packages to support JS code generation

examples/hello-world/package.json

@@ -15,7 +15,6 @@
     "@sdeverywhere/build": "^0.3.4",
     "@sdeverywhere/cli": "^0.7.23",
     "@sdeverywhere/plugin-check": "^0.3.5",
-    "@sdeverywhere/plugin-wasm": "^0.2.3",
     "@sdeverywhere/plugin-worker": "^0.2.3",
     "vite": "^4.4.9"
   }

examples/hello-world/sde.config.js

@@ -1,5 +1,4 @@
 import { checkPlugin } from '@sdeverywhere/plugin-check'
-import { wasmPlugin } from '@sdeverywhere/plugin-wasm'
 import { workerPlugin } from '@sdeverywhere/plugin-worker'
 
 export async function config() {
@@ -15,10 +14,7 @@ export async function config() {
     },
 
     plugins: [
-      // Generate a `generated-model.js` file containing the Wasm model
-      wasmPlugin(),
-
-      // Generate a `worker.js` file that runs the Wasm model in a worker
+      // Generate a `worker.js` file that runs the generated model in a worker
       workerPlugin(),
 
       // Run model check

examples/sir/README.md

@@ -1,6 +1,6 @@
 # sir
 
-This example directory contains the class SIR (Susceptible-Infectious-Recovered) model of
+This example directory contains the classic SIR (Susceptible-Infectious-Recovered) model of
 infectious disease.
 It is intended to demonstrate the use of the `@sdeverywhere/create` package to quickly
 set up a new project that uses the provided config files to generate a simple web application.

examples/template-default/sde.config.js

@@ -13,8 +13,27 @@ const packagePath = (...parts) => joinPath(__dirname, 'packages', ...parts)
 const appPath = (...parts) => packagePath('app', ...parts)
 const corePath = (...parts) => packagePath('core', ...parts)
 
+//
+// NOTE: This template can generate a model as a WebAssembly module (runs faster,
+// but requires additional tools to be installed) or in pure JavaScript format (runs
+// slower, but is simpler to build).  Regardless of which approach you choose, the
+// same APIs (e.g., `ModelRunner`) can be used to run the generated model.
+//
+// If `genFormat` is 'c', the sde compiler will generate C code, but `plugin-wasm`
+// is needed to convert the C code to a WebAssembly module, in which case
+// the Emscripten SDK must be installed (the `@sdeverywhere/create` package can
+// help with this; see "Quick Start" instructions).
+//
+// If `genFormat` is 'js', the sde compiler will generate JavaScript code that runs
+// in the browser or in Node.js without the additional Emscripten build step.
+//
+const genFormat = 'js'
+
 export async function config() {
   return {
+    // Specify the format of the generated code, either 'js' or 'c'
+    genFormat,
+
     // Specify the Vensim model to read
     modelFiles: ['MODEL_NAME.mdl'],
 
@@ -34,10 +53,12 @@ export async function config() {
     }),
 
     plugins: [
-      // Generate a `generated-model.js` file containing the Wasm model
-      wasmPlugin(),
+      // If targeting WebAssembly, generate a `generated-model.js` file
+      // containing the Wasm model
+      genFormat === 'c' && wasmPlugin(),
 
-      // Generate a `worker.js` file that runs the Wasm model in a worker
+      // Generate a `worker.js` file that runs the model asynchronously on a
+      // worker thread for improved responsiveness
       workerPlugin({
         outputPaths: [corePath('src', 'model', 'generated', 'worker.js')]
       }),

examples/template-minimal/sde.config.js

@@ -2,8 +2,28 @@ import { checkPlugin } from '@sdeverywhere/plugin-check'
 import { wasmPlugin } from '@sdeverywhere/plugin-wasm'
 import { workerPlugin } from '@sdeverywhere/plugin-worker'
 
+//
+// NOTE: This template can generate a model as a WebAssembly module (runs faster,
+// but requires additional tools to be installed) or in pure JavaScript format (runs
+// slower, but is simpler to build).  Regardless of which approach you choose, the
+// same APIs (e.g., `ModelRunner`) can be used to run the generated model.
+//
+// If `genFormat` is 'c', the sde compiler will generate C code, but `plugin-wasm`
+// is needed to convert the C code to a WebAssembly module, in which case
+// the Emscripten SDK must be installed (the `@sdeverywhere/create` package can
+// help with this; see "Quick Start" instructions).
+//
+// If `genFormat` is 'js', the sde compiler will generate JavaScript code that runs
+// in the browser or in Node.js without the additional Emscripten build step.
+//
+const genFormat = 'js'
+
 export async function config() {
   return {
+    // Specify the format of the generated code, either 'js' or 'c'
+    genFormat,
+
+    // Specify the Vensim model to read
     modelFiles: ['MODEL_NAME.mdl'],
 
     modelSpec: async () => {
@@ -24,10 +44,12 @@ export async function config() {
     },
 
     plugins: [
-      // Generate a `generated-model.js` file containing the Wasm model
-      wasmPlugin(),
+      // If targeting WebAssembly, generate a `generated-model.js` file
+      // containing the Wasm model
+      genFormat === 'c' && wasmPlugin(),
 
-      // Generate a `worker.js` file that runs the Wasm model in a worker
+      // Generate a `worker.js` file that runs the model asynchronously on a
+      // worker thread for improved responsiveness
       workerPlugin(),
 
       // Run model check

packages/build/docs/interfaces/Plugin.md

@@ -13,8 +13,8 @@ listed below:
   - preGenerate
       - preProcessMdl
       - postProcessMdl
-      - preGenerateC
-      - postGenerateC
+      - preGenerateCode
+      - postGenerateCode
   - postGenerate
   - postBuild
   - watch (only called once after initial build steps when mode==development)
@@ -100,42 +100,44 @@ The modified mdl file content (if postprocessing was needed).
 
 ___
 
-### preGenerateC
+### preGenerateCode
 
-`Optional` **preGenerateC**(`context`): `Promise`<`void`\>
+`Optional` **preGenerateCode**(`context`, `format`): `Promise`<`void`\>
 
-Called before SDE generates a C file from the mdl file.
+Called before SDE generates a JS or C file from the mdl file.
 
 #### Parameters
 
 | Name | Type | Description |
 | :------ | :------ | :------ |
 | `context` | [`BuildContext`](../classes/BuildContext.md) | The build context (for logging, etc). |
+| `format` | ``"js"`` \| ``"c"`` | The generated code format, either 'js' or 'c'. |
 
 #### Returns
 
 `Promise`<`void`\>
 
 ___
 
-### postGenerateC
+### postGenerateCode
 
-`Optional` **postGenerateC**(`context`, `cContent`): `Promise`<`string`\>
+`Optional` **postGenerateCode**(`context`, `format`, `content`): `Promise`<`string`\>
 
-Called after SDE generates a C file from the mdl file.
+Called after SDE generates a JS or C file from the mdl file.
 
 #### Parameters
 
 | Name | Type | Description |
 | :------ | :------ | :------ |
 | `context` | [`BuildContext`](../classes/BuildContext.md) | The build context (for logging, etc). |
-| `cContent` | `string` | The resulting C file content. |
+| `format` | ``"js"`` \| ``"c"`` | The generated code format, either 'js' or 'c'. |
+| `content` | `string` | The resulting JS or C file content. |
 
 #### Returns
 
 `Promise`<`string`\>
 
-The modified C file content (if postprocessing was needed).
+The modified JS or C file content (if postprocessing was needed).
 
 ___
 

packages/build/docs/interfaces/ResolvedConfig.md

@@ -57,3 +57,13 @@ ___
 
 Paths to files that when changed will trigger a rebuild in watch mode.  These
 can be paths to files or glob patterns (relative to the project directory).
+
+___
+
+### genFormat
+
+ **genFormat**: ``"js"`` \| ``"c"``
+
+The code format to generate.  If 'js', the model will be compiled to a JavaScript
+file.  If 'c', the model will be compiled to a C file (in which case an additional
+plugin will be needed to convert the C code to a WebAssembly module).

packages/build/docs/interfaces/UserConfig.md

@@ -53,6 +53,17 @@ If left undefined, this will resolve to the `modelFiles` array.
 
 ___
 
+### genFormat
+
+ `Optional` **genFormat**: ``"js"`` \| ``"c"``
+
+The code format to generate.  If 'js', the model will be compiled to a JavaScript
+file.  If 'c', the model will be compiled to a C file (in which case an additional
+plugin will be needed to convert the C code to a WebAssembly module).  If undefined,
+defaults to 'js'.
+
+___
+
 ### plugins
 
  `Optional` **plugins**: [`Plugin`](Plugin.md)[]

packages/build/src/_shared/resolved-config.ts

@@ -42,6 +42,13 @@ export interface ResolvedConfig {
    */
   watchPaths: string[]
 
+  /**
+   * The code format to generate.  If 'js', the model will be compiled to a JavaScript
+   * file.  If 'c', the model will be compiled to a C file (in which case an additional
+   * plugin will be needed to convert the C code to a WebAssembly module).
+   */
+  genFormat: 'js' | 'c'
+
   /**
    * The path to the `@sdeverywhere/cli` package.  This is currently only used to get
    * access to the files in the `src/c` directory.

packages/build/src/build/impl/gen-model.ts

@@ -58,22 +58,35 @@ export async function generateModel(context: BuildContext, plugins: Plugin[]): P
     }
   }
 
-  // Generate the C file
+  // Generate the JS or C file
   for (const plugin of plugins) {
-    if (plugin.preGenerateC) {
-      await plugin.preGenerateC(context)
+    if (plugin.preGenerateCode) {
+      await plugin.preGenerateCode(context, config.genFormat)
     }
   }
-  await generateC(context, config.sdeDir, sdeCmdPath, prepDir)
+  await generateCode(context, config.sdeDir, sdeCmdPath, prepDir)
+  const generatedCodeFile = `processed.${config.genFormat}`
+  const generatedCodePath = joinPath(prepDir, 'build', generatedCodeFile)
   for (const plugin of plugins) {
-    if (plugin.postGenerateC) {
-      const cPath = joinPath(prepDir, 'build', 'processed.c')
-      let cContent = await readFile(cPath, 'utf8')
-      cContent = await plugin.postGenerateC(context, cContent)
-      await writeFile(cPath, cContent)
+    if (plugin.postGenerateCode) {
+      let generatedCodeContent = await readFile(generatedCodePath, 'utf8')
+      generatedCodeContent = await plugin.postGenerateCode(context, config.genFormat, generatedCodeContent)
+      await writeFile(generatedCodePath, generatedCodeContent)
     }
   }
 
+  if (config.genFormat === 'js') {
+    // When generating JS code, copy the generated JS file to the `staged/model`
+    // directory, because that's where plugin-worker expects to find it, but also
+    // set it up to be copied to the `prepDir`, which is where other code expects
+    // to find it
+    // TODO: Maybe we can change plugin-worker to use the one in `prepDir`, and/or
+    // add a build config setting to allow for customizing the output location
+    const outputJsFile = 'generated-model.js'
+    const stagedOutputJsPath = context.prepareStagedFile('model', outputJsFile, prepDir, outputJsFile)
+    await copyFile(generatedCodePath, stagedOutputJsPath)
+  }
+
   const t1 = performance.now()
   const elapsed = ((t1 - t0) / 1000).toFixed(1)
   log('info', `Done generating model (${elapsed}s)`)
@@ -165,36 +178,43 @@ async function flattenMdls(
 }
 
 /**
- * Generate a C file from the `processed.mdl` file.
+ * Generate a JS or C file from the `processed.mdl` file.
  */
-async function generateC(context: BuildContext, sdeDir: string, sdeCmdPath: string, prepDir: string): Promise<void> {
-  log('verbose', '  Generating C code')
+async function generateCode(context: BuildContext, sdeDir: string, sdeCmdPath: string, prepDir: string): Promise<void> {
+  const genFormat = context.config.genFormat
+  const genFormatName = genFormat.toUpperCase()
+  log('verbose', `  Generating ${genFormatName} code`)
 
-  // Use SDE to generate both a C version of the model (`--genc`) AND a JSON list of all model
+  // Use SDE to generate both a JS/C version of the model (`--outformat`) AND a JSON list of all model
   // dimensions and variables (`--list`)
   const command = sdeCmdPath
-  const gencArgs = ['generate', '--genc', '--list', '--spec', 'spec.json', 'processed']
-  const gencOutput = await context.spawnChild(prepDir, command, gencArgs, {
+  const outFormat = `--outformat=${genFormat}`
+  const genCmdArgs = ['generate', outFormat, '--list', '--spec', 'spec.json', 'processed']
+  const genCmdOutput = await context.spawnChild(prepDir, command, genCmdArgs, {
     // By default, ignore lines that start with "WARNING: Data for" since these are often harmless
     // TODO: Don't filter by default, but make it configurable
     // ignoredMessageFilter: 'WARNING: Data for'
     // The default error message from `spawnChild` is not very informative, so the
     // following allows us to throw our own error
     ignoreError: true
   })
-  if (gencOutput.exitCode !== 0) {
-    throw new Error(`Failed to generate C code: 'sde generate' command failed (code=${gencOutput.exitCode})`)
+  if (genCmdOutput.exitCode !== 0) {
+    throw new Error(
+      `Failed to generate ${genFormatName} code: 'sde generate' command failed (code=${genCmdOutput.exitCode})`
+    )
   }
 
-  // Copy SDE's supporting C files into the build directory
-  const buildDir = joinPath(prepDir, 'build')
-  const sdeCDir = joinPath(sdeDir, 'src', 'c')
-  const files = await readdir(sdeCDir)
-  const copyOps = []
-  for (const file of files) {
-    if (file.endsWith('.c') || file.endsWith('.h')) {
-      copyOps.push(copyFile(joinPath(sdeCDir, file), joinPath(buildDir, file)))
+  if (genFormat === 'c') {
+    // Copy SDE's supporting C files into the build directory
+    const buildDir = joinPath(prepDir, 'build')
+    const sdeCDir = joinPath(sdeDir, 'src', 'c')
+    const files = await readdir(sdeCDir)
+    const copyOps = []
+    for (const file of files) {
+      if (file.endsWith('.c') || file.endsWith('.h')) {
+        copyOps.push(copyFile(joinPath(sdeCDir, file), joinPath(buildDir, file)))
+      }
     }
+    await Promise.all(copyOps)
   }
-  await Promise.all(copyOps)
 }

packages/build/src/config/config-loader.ts

@@ -157,13 +157,28 @@ function resolveUserConfig(
     watchPaths = modelFiles
   }
 
+  // Validate the code generation format
+  const rawGenFormat = userConfig.genFormat || 'js'
+  let genFormat: 'js' | 'c'
+  switch (rawGenFormat) {
+    case 'js':
+      genFormat = 'js'
+      break
+    case 'c':
+      genFormat = 'c'
+      break
+    default:
+      throw new Error(`The configured genFormat value is invalid; must be either 'js' or 'c'`)
+  }
+
   return {
     mode,
     rootDir,
     prepDir,
     modelFiles,
     modelInputPaths,
     watchPaths,
+    genFormat,
     sdeDir,
     sdeCmdPath
   }

packages/build/src/config/user-config.ts

@@ -40,6 +40,14 @@ export interface UserConfig {
    */
   watchPaths?: string[]
 
+  /**
+   * The code format to generate.  If 'js', the model will be compiled to a JavaScript
+   * file.  If 'c', the model will be compiled to a C file (in which case an additional
+   * plugin will be needed to convert the C code to a WebAssembly module).  If undefined,
+   * defaults to 'js'.
+   */
+  genFormat?: 'js' | 'c'
+
   /**
    * The array of plugins that are used to customize the build process.  These will be
    * executed in the order defined here.