Move consolePrinter to its own file to expose it as a public API

Author: kateinoigakukun

packages/npm-packages/ruby-wasm-wasi/src/browser.ts

@@ -1,64 +1,6 @@
 import { init, WASI } from "@wasmer/wasi";
 import { RubyVM } from "./index.js";
-
-const consolePrinter = () => {
-  let memory: WebAssembly.Memory | undefined = undefined;
-  let view: DataView | undefined = undefined;
-
-  const decoder = new TextDecoder();
-
-  return {
-    addToImports(imports: WebAssembly.Imports): void {
-      const original = imports.wasi_snapshot_preview1.fd_write as (
-        fd: number,
-        iovs: number,
-        iovsLen: number,
-        nwritten: number,
-      ) => number;
-      imports.wasi_snapshot_preview1.fd_write = (
-        fd: number,
-        iovs: number,
-        iovsLen: number,
-        nwritten: number,
-      ): number => {
-        if (fd !== 1 && fd !== 2) {
-          return original(fd, iovs, iovsLen, nwritten);
-        }
-
-        if (typeof memory === "undefined" || typeof view === "undefined") {
-          throw new Error("Memory is not set");
-        }
-        if (view.buffer.byteLength === 0) {
-          view = new DataView(memory.buffer);
-        }
-
-        const buffers = Array.from({ length: iovsLen }, (_, i) => {
-          const ptr = iovs + i * 8;
-          const buf = view.getUint32(ptr, true);
-          const bufLen = view.getUint32(ptr + 4, true);
-          return new Uint8Array(memory.buffer, buf, bufLen);
-        });
-
-        let written = 0;
-        let str = "";
-        for (const buffer of buffers) {
-          str += decoder.decode(buffer);
-          written += buffer.byteLength;
-        }
-        view.setUint32(nwritten, written, true);
-
-        const log = fd === 1 ? console.log : console.warn;
-        log(str);
-
-        return 0;
-      };
-    },
-    setMemory(m: WebAssembly.Memory) {
-      memory = m;
-      view = new DataView(m.buffer);
-    },
-  };
-};
+import { consolePrinter } from "./console.js";
 
 export const DefaultRubyVM = async (
   rubyModule: WebAssembly.Module,

packages/npm-packages/ruby-wasm-wasi/src/console.ts

@@ -0,0 +1,95 @@
+/**
+ * Create a console printer that can be used as an overlay of WASI imports.
+ * See the example below for how to use it.
+ *
+ * ```javascript
+ * const imports = {
+ *  "wasi_snapshot_preview1": wasi.wasiImport,
+ * }
+ * const printer = consolePrinter();
+ * printer.addToImports(imports);
+ *
+ * const instance = await WebAssembly.instantiate(module, imports);
+ * printer.setMemory(instance.exports.memory);
+ * ```
+ *
+ * Note that the `stdout` and `stderr` functions are called with text, not
+ * bytes. This means that bytes written to stdout/stderr will be decoded as
+ * UTF-8 and then passed to the `stdout`/`stderr` functions every time a write
+ * occurs without buffering.
+ *
+ * @param stdout A function that will be called when stdout is written to.
+ *               Defaults to `console.log`.
+ * @param stderr A function that will be called when stderr is written to.
+ *               Defaults to `console.warn`.
+ * @returns An object that can be used as an overlay of WASI imports.
+ */
+export function consolePrinter(
+  {
+    stdout,
+    stderr,
+  }: {
+    stdout: (str: string) => void;
+    stderr: (str: string) => void;
+  } = {
+    stdout: console.log,
+    stderr: console.warn,
+  },
+) {
+  let memory: WebAssembly.Memory | undefined = undefined;
+  let view: DataView | undefined = undefined;
+
+  const decoder = new TextDecoder();
+
+  return {
+    addToImports(imports: WebAssembly.Imports): void {
+      const original = imports.wasi_snapshot_preview1.fd_write as (
+        fd: number,
+        iovs: number,
+        iovsLen: number,
+        nwritten: number,
+      ) => number;
+      imports.wasi_snapshot_preview1.fd_write = (
+        fd: number,
+        iovs: number,
+        iovsLen: number,
+        nwritten: number,
+      ): number => {
+        if (fd !== 1 && fd !== 2) {
+          return original(fd, iovs, iovsLen, nwritten);
+        }
+
+        if (typeof memory === "undefined" || typeof view === "undefined") {
+          throw new Error("Memory is not set");
+        }
+        if (view.buffer.byteLength === 0) {
+          view = new DataView(memory.buffer);
+        }
+
+        const buffers = Array.from({ length: iovsLen }, (_, i) => {
+          const ptr = iovs + i * 8;
+          const buf = view.getUint32(ptr, true);
+          const bufLen = view.getUint32(ptr + 4, true);
+          return new Uint8Array(memory.buffer, buf, bufLen);
+        });
+
+        let written = 0;
+        let str = "";
+        for (const buffer of buffers) {
+          str += decoder.decode(buffer);
+          written += buffer.byteLength;
+        }
+        view.setUint32(nwritten, written, true);
+
+        const log = fd === 1 ? stdout : stderr;
+        log(str);
+
+        return 0;
+      };
+    },
+    setMemory(m: WebAssembly.Memory) {
+      memory = m;
+      view = new DataView(m.buffer);
+    },
+  };
+}