Option to not inline wasm

packages/wasm/README.md

@@ -36,9 +36,9 @@ export default {
   input: 'src/index.js',
   output: {
     dir: 'output',
-    format: 'cjs'
+    format: 'cjs',
   },
-  plugins: [wasm()]
+  plugins: [wasm()],
 };
 ```
 
@@ -53,6 +53,22 @@ Default: `null`
 
 Specifies an array of strings that each represent a WebAssembly file to load synchronously. See [Synchronous Modules](#synchronous-modules) for a functional example.
 
+### `limit`
+
+Type: `Number`<br>
+Default: `14336` (14kb)
+
+The file size limit for inline files. If a file exceeds this limit, it will be copied to the destination folder and loaded from a separate file at runtime. If `limit` is set to `0` all files will be copied.
+
+Files specified in `sync` to load synchronously are always inlined, regardless of size.
+
+### `publicPath`
+
+Type: `String`<br>
+Default: (empty string)
+
+A string which will be added in front of filenames when they are not inlined but are copied.
+
 ## WebAssembly Example
 
 Given the following simple C file:
@@ -83,7 +99,7 @@ Small modules (< 4KB) can be compiled synchronously by specifying them in the co
 
 ```js
 wasm({
-  sync: ['web/sample.wasm', 'web/foobar.wasm']
+  sync: ['web/sample.wasm', 'web/foobar.wasm'],
 });
 ```
 

packages/wasm/src/index.ts

@@ -1,34 +1,83 @@
-import { readFile } from 'fs';
-import { resolve } from 'path';
+import * as fs from 'fs';
+import * as path from 'path';
+import { promisify } from 'util';
+import { createHash } from 'crypto';
+
+import { assert } from 'console';
 
 import { Plugin } from 'rollup';
 
 import { RollupWasmOptions } from '../types';
 
+const makeDir = require('make-dir');
+
+const fsStatPromise = promisify(fs.stat);
+const fsReadFilePromise = promisify(fs.readFile);
+
 export function wasm(options: RollupWasmOptions = {}): Plugin {
-  const syncFiles = (options.sync || []).map((x) => resolve(x));
+  const { sync = [], limit = 14 * 1024, publicPath = '' } = options;
+
+  const syncFiles = sync.map((x) => path.resolve(x));
+  const copies = Object.create(null);
 
   return {
     name: 'wasm',
 
     load(id) {
-      if (/\.wasm$/.test(id)) {
-        return new Promise((res, reject) => {
-          readFile(id, (error, buffer) => {
-            if (error != null) {
-              reject(error);
-            }
-            res(buffer.toString('binary'));
-          });
-        });
+      if (!/\.wasm$/.test(id)) {
+        return null;
       }
-      return null;
+
+      return Promise.all([fsStatPromise(id), fsReadFilePromise(id)]).then(([stats, buffer]) => {
+        if ((limit && stats.size > limit) || limit === 0) {
+          const hash = createHash('sha1')
+            .update(buffer)
+            .digest('hex')
+            .substr(0, 16);
+
+          // only copy if the file is not marked `sync`, `sync` files are always inlined
+          if (syncFiles.indexOf(id) === -1) {
+            copies[id] = `${publicPath}${hash}.wasm`;
+          }
+        }
+
+        return buffer.toString('binary');
+      });
     },
 
     banner: `
-      function _loadWasmModule (sync, src, imports) {
+      function _loadWasmModule (sync, filepath, src, imports) {
+        function _instantiateOrCompile(source, imports, stream) {
+          var instantiateFunc = stream ? WebAssembly.instantiateStreaming : WebAssembly.instantiate;
+          var compileFunc = stream ? WebAssembly.compileStreaming : WebAssembly.compile;
+
+          if (imports) {
+            return instantiateFunc(source, imports)
+          } else {
+            return compileFunc(source)
+          }
+        }
+
         var buf = null
         var isNode = typeof process !== 'undefined' && process.versions != null && process.versions.node != null
+
+        if (filepath && isNode) {
+          var fs = eval('require("fs")')
+          var path = eval('require("path")')
+
+          return new Promise((resolve, reject) => {
+            fs.readFile(path.resolve(__dirname, filepath), (error, buffer) => {
+              if (error != null) {
+                reject(error)
+              }
+
+              resolve(_instantiateOrCompile(buffer, imports, false))
+            });
+          });
+        } else if (filepath) {
+          return _instantiateOrCompile(fetch(filepath), imports, true)
+        }
+
         if (isNode) {
           buf = Buffer.from(src, 'base64')
         } else {
@@ -40,26 +89,66 @@ export function wasm(options: RollupWasmOptions = {}): Plugin {
           }
         }
 
-        if (imports && !sync) {
-          return WebAssembly.instantiate(buf, imports)
-        } else if (!imports && !sync) {
-          return WebAssembly.compile(buf)
-        } else {
+        if(sync) {
           var mod = new WebAssembly.Module(buf)
           return imports ? new WebAssembly.Instance(mod, imports) : mod
+        } else {
+          return _instantiateOrCompile(buf, imports, false)
         }
       }
     `.trim(),
 
     transform(code, id) {
       if (code && /\.wasm$/.test(id)) {
-        const src = Buffer.from(code, 'binary').toString('base64');
-        const sync = syncFiles.indexOf(id) !== -1;
-        return `export default function(imports){return _loadWasmModule(${+sync}, '${src}', imports)}`;
+        const isSync = syncFiles.indexOf(id) !== -1;
+        const filepath = copies[id] ? `'${copies[id]}'` : null;
+        let src;
+
+        if (filepath === null) {
+          assert(!isSync, 'non-inlined files can not be `sync`.');
+          src = Buffer.from(code, 'binary').toString('base64');
+          src = `'${src}'`;
+        } else {
+          src = null;
+        }
+
+        return `export default function(imports){return _loadWasmModule(${+isSync}, ${filepath}, ${src}, imports)}`;
       }
       return null;
+    },
+    generateBundle: async function write(outputOptions) {
+      // can't generate anything if we can't determine the output base
+      if (!outputOptions.dir && !outputOptions.file) {
+        return;
+      }
+
+      const base = outputOptions.dir || path.dirname(outputOptions.file);
+
+      await makeDir(base);
+
+      await Promise.all(
+        Object.keys(copies).map(async (name) => {
+          const output = copies[name];
+          // Create a nested directory if the fileName pattern contains
+          // a directory structure
+          const outputDirectory = path.join(base, path.dirname(output));
+          await makeDir(outputDirectory);
+          return copy(name, path.join(base, output));
+        })
+      );
     }
   };
 }
 
+function copy(src, dest) {
+  return new Promise((resolve, reject) => {
+    const read = fs.createReadStream(src);
+    read.on('error', reject);
+    const write = fs.createWriteStream(dest);
+    write.on('error', reject);
+    write.on('finish', resolve);
+    read.pipe(write);
+  });
+}
+
 export default wasm;

packages/wasm/test/snapshots/test.js.md

@@ -0,0 +1,13 @@
+# Snapshot report for `test/test.js`
+
+The actual snapshot is saved in `test.js.snap`.
+
+Generated by [AVA](https://avajs.dev).
+
+## fetching WASM from separate file
+
+> Snapshot 1
+
+    [
+      'output/85cebae0fa1ae813.wasm',
+    ]

packages/wasm/test/test.js

@@ -1,12 +1,21 @@
+import { sep, posix, join } from 'path';
+
 import { rollup } from 'rollup';
+import globby from 'globby';
 import test from 'ava';
+import del from 'del';
 
 import { getCode } from '../../../util/test';
 
 import wasm from '../';
 
 const AsyncFunction = Object.getPrototypeOf(async () => {}).constructor;
 
+process.chdir(__dirname);
+
+const outputFile = './output/bundle.js';
+const outputDir = './output/';
+
 const testBundle = async (t, bundle) => {
   const code = await getCode(bundle);
   const func = new AsyncFunction('t', `let result;\n\n${code}\n\nreturn result;`);
@@ -17,17 +26,43 @@ test('async compiling', async (t) => {
   t.plan(2);
 
   const bundle = await rollup({
-    input: 'test/fixtures/async.js',
+    input: 'fixtures/async.js',
     plugins: [wasm()]
   });
   await testBundle(t, bundle);
 });
 
+test('fetching WASM from separate file', async (t) => {
+  t.plan(3);
+
+  const bundle = await rollup({
+    input: 'fixtures/complex.js',
+    plugins: [
+      wasm({
+        limit: 0
+      })
+    ]
+  });
+
+  await bundle.write({ format: 'cjs', file: outputFile });
+  const glob = join(outputDir, `**/*.wasm`)
+    .split(sep)
+    .join(posix.sep);
+
+  global.result = null;
+  global.t = t;
+  require(outputFile);
+
+  await global.result;
+  t.snapshot(await globby(glob));
+  await del(outputDir);
+});
+
 test('complex module decoding', async (t) => {
   t.plan(2);
 
   const bundle = await rollup({
-    input: 'test/fixtures/complex.js',
+    input: 'fixtures/complex.js',
     plugins: [wasm()]
   });
   await testBundle(t, bundle);
@@ -37,10 +72,10 @@ test('sync compiling', async (t) => {
   t.plan(2);
 
   const bundle = await rollup({
-    input: 'test/fixtures/sync.js',
+    input: 'fixtures/sync.js',
     plugins: [
       wasm({
-        sync: ['test/fixtures/sample.wasm']
+        sync: ['fixtures/sample.wasm']
       })
     ]
   });
@@ -51,10 +86,10 @@ test('imports', async (t) => {
   t.plan(1);
 
   const bundle = await rollup({
-    input: 'test/fixtures/imports.js',
+    input: 'fixtures/imports.js',
     plugins: [
       wasm({
-        sync: ['test/fixtures/imports.wasm']
+        sync: ['fixtures/imports.wasm']
       })
     ]
   });
@@ -67,7 +102,7 @@ try {
     t.plan(2);
 
     const bundle = await rollup({
-      input: 'test/fixtures/worker.js',
+      input: 'fixtures/worker.js',
       plugins: [wasm()]
     });
     const code = await getCode(bundle);

packages/wasm/types/index.d.ts

@@ -5,6 +5,16 @@ export interface RollupWasmOptions {
    * Specifies an array of strings that each represent a WebAssembly file to load synchronously.
    */
   sync?: readonly string[];
+  /**
+   * The file size limit for inline files. If a file exceeds this limit, it will be copied to the destination folder and loaded from a separate file at runtime.
+   * If `limit` is set to `0` all files will be copied.
+   * Files specified in `sync` to load synchronously are always inlined, regardless of size.
+   */
+  limit?: Number;
+  /**
+   * A string which will be added in front of filenames when they are not inlined but are copied.
+   */
+  publicPath?: string;
 }
 
 /**