feat(evalCodeBlock): handle JS; closes #40

md/codeBlock/eval.test.ts

@@ -16,6 +16,7 @@ import * as fenced from "./fenced.ts";
 import * as indented from "./indented.ts";
 
 const throws = "throw new Error()";
+const logs = 'console.log("logged")';
 
 describe("evaluate", () => {
   test("no lang", () => {
@@ -32,7 +33,7 @@ describe("evaluate", () => {
 
   test("unknown lang", () =>
     void assertRejects(
-      async () => void await evaluate(fenced.create(throws, { lang: "js" })),
+      async () => void await evaluate(fenced.create(throws, { lang: "ZZZ" })),
       UnknownLanguageError,
     ));
 
@@ -44,6 +45,15 @@ describe("evaluate", () => {
     assertEquals(result.stdout, "");
     assert(result.stderr.includes("throw new Error()"));
   });
+
+  test("javascript", async () => {
+    assertEquals(await evaluate(fenced.create(logs, { lang: "js" })), {
+      success: true,
+      code: 0,
+      stderr: "",
+      stdout: "logged",
+    });
+  });
 });
 
 describe("evaluateAll", () => {

md/codeBlock/eval.ts

@@ -2,9 +2,19 @@ import { parse as parseCodeBlock } from "./parse.ts";
 import { findAll as findAllCodeBlocks } from "./findAll.ts";
 import type { CmdResult } from "../../cli/cmd.ts";
 import { evaluate as evalTS } from "../../ts/evaluate.ts";
+import { evaluate as evalJS } from "../../js/evaluate.ts";
 import type { CodeBlockDetails } from "./types.ts";
 import type { TextLocation } from "../../string/Text.ts";
 
+const LANGS = {
+  ts: evalTS,
+  js: evalJS,
+};
+
+function _isRegistered(lang: string): lang is keyof typeof LANGS {
+  return lang in LANGS;
+}
+
 export class IndentedCodeBlockError extends Error {
   constructor() {
     super("Indented code blocks are not supported");
@@ -30,33 +40,25 @@ export type EvaluateOptions = {
   replace?: [string | RegExp, string][];
 };
 
-function _getCode(
-  details: CodeBlockDetails,
-  replace: Exclude<EvaluateOptions["replace"], undefined>,
-): string {
+/** Evaluate a TS or JS code block. Uses `ts/evaluate` and `js/evaluate`. */
+export async function evaluate(
+  codeBlock: string | CodeBlockDetails,
+  { replace = [] }: EvaluateOptions = {},
+): Promise<CmdResult> {
+  const details = typeof codeBlock === "string"
+    ? parseCodeBlock(codeBlock)
+    : codeBlock;
+
   if (details.type === "indented") throw new IndentedCodeBlockError();
 
-  const { lang, code } = details;
+  const lang = details.lang;
+  let code = details.code;
 
   if (!lang) throw new NoLanguageError();
+  if (!_isRegistered(lang)) throw new UnknownLanguageError(lang);
+  for (const [before, after] of replace) code = code.replaceAll(before, after);
 
-  if (lang !== "ts") throw new UnknownLanguageError(lang);
-
-  return replace.reduce(
-    (code, [search, replace]) => code.replaceAll(search, replace),
-    code,
-  );
-}
-
-/** Passes a code block to `deno eval`. */
-export async function evaluate(
-  codeBlock: string,
-  { replace = [] }: EvaluateOptions = {},
-): Promise<CmdResult> {
-  const details = parseCodeBlock(codeBlock);
-  const code = _getCode(details, replace);
-
-  return await evalTS(code);
+  return await LANGS[lang](code);
 }
 
 export type EvaluateAllResult = [
@@ -80,9 +82,7 @@ export async function evaluateAll(
 
   for (const [details, location] of findAllCodeBlocks(markdown)) {
     try {
-      const code = _getCode(details, replace);
-
-      results.push([details, location, await evalTS(code)]);
+      results.push([details, location, await evaluate(details, { replace })]);
     } catch (error) {
       if (
         error instanceof IndentedCodeBlockError ||

readme.md

@@ -265,7 +265,7 @@ codeBlock.evaluate(
 
 ### `script/evalCodeBlocks`
 
-For a markdown file, execute each TS code block in the file. Useful for checking imports and examples in a readme.
+For a markdown file, execute each TS or JS code block in the file. Useful for checking imports and examples in a readme.
 
 ```ts
 import { evalCodeBlocks } from "https://deno.land/x/handy/md/script/evalCodeBlocks.ts";