From 451dad4d411c85352fdb15bc02c18809a0128c8a Mon Sep 17 00:00:00 2001
From: Yimiprod <yimiprod@gmail.com>
Date: Mon, 12 Feb 2024 16:11:01 +0100
Subject: [PATCH] feat(Instance)!: parser throw when default async is true and
 called with async at false

BREAKING CHANGE: parser now throw an error when `defaultConfig` is modified by an extension to make the returned value a Promise and the we call parser with `async` option at false.
It can be skipped with `silent` to true, making it still working for library that use it to modify the config globally but still calling each instance with the option `async` at false.
---
 src/Instance.ts          |  4 ++--
 src/MarkedOptions.ts     |  4 ++--
 test/types/marked.ts     | 16 ++++++++++++++--
 test/unit/marked.test.js | 20 +++++++++++++++++++-
 4 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/src/Instance.ts b/src/Instance.ts
index 9b99cd56871..58fd1fdc6f1 100644
--- a/src/Instance.ts
+++ b/src/Instance.ts
@@ -273,10 +273,10 @@ export class Marked {
       const origOpt: MarkedOptions = { ...options };
       const opt: MarkedOptions = { ...this.defaults, ...origOpt };
 
-      // Show warning if an extension set async to true but the parse was called with async: false
       if (isAsyncOptions(this.defaults) && isSyncOptions(origOpt)) {
+        // Throw an error if an extension set async to true but the parse was called with async: false
         if (!opt.silent) {
-          console.warn('marked(): The async option was set to true by an extension. The async: false option sent to parse will be ignored.');
+          throw new Error('marked(): The async option was set to true by an extension. The async: false option sent to parse will be ignored.');
         }
 
         opt.async = true;
diff --git a/src/MarkedOptions.ts b/src/MarkedOptions.ts
index d1b73c779b1..8ad955d71e1 100644
--- a/src/MarkedOptions.ts
+++ b/src/MarkedOptions.ts
@@ -162,9 +162,9 @@ export interface MarkedAsyncOptions extends _MarkedOptions {
 export type MarkedOptions = MarkedSyncOptions | MarkedAsyncOptions;
 
 export function isAsyncOptions(options: MarkedOptions): options is MarkedAsyncOptions {
-  return 'async' in options && options.async === true;
+  return options.async === true;
 }
 
 export function isSyncOptions(options: MarkedOptions): options is MarkedSyncOptions {
-  return !isAsyncOptions(options);
+  return options.async === false;
 }
diff --git a/test/types/marked.ts b/test/types/marked.ts
index de2bd4bdd28..414b82d4d77 100644
--- a/test/types/marked.ts
+++ b/test/types/marked.ts
@@ -261,13 +261,25 @@ marked.use(asyncExtension);
 const md = '# foobar';
 const asyncMarked: string = await marked(md, { async: true });
 const promiseMarked: Promise<string> = marked(md, { async: true });
-const notAsyncMarked: string = marked(md, { async: false });
+const notAsyncMarked: string = marked(md, { async: false, silent: true });
 const defaultMarked: string = marked(md);
 
 const asyncMarkedParse: string = await marked.parse(md, { async: true });
 const promiseMarkedParse: Promise<string> = marked.parse(md, { async: true });
-const notAsyncMarkedParse: string = marked.parse(md, { async: false });
+const notAsyncMarkedParse: string = marked.parse(md, { async: false, silent: true });
 const defaultMarkedParse: string = marked.parse(md);
+
+try {
+  const notAsyncMarkedThrow: string = marked(md, { async: false, silent: false });
+} catch {
+  console.log('expected throw');
+}
+
+try {
+  const notAsyncMarkedParseThrow: string = marked.parse(md, { async: false, silent: false });
+} catch {
+  console.log('expected throw');
+}
 })();
 
 // Tests for List and ListItem
diff --git a/test/unit/marked.test.js b/test/unit/marked.test.js
index c9c0925a128..9bc1faaccdd 100644
--- a/test/unit/marked.test.js
+++ b/test/unit/marked.test.js
@@ -632,7 +632,25 @@ used extension2 walked</p>
     it('should return Promise if async is set by extension', () => {
       marked.use({ async: true });
 
-      assert.ok(marked.parse('test', { async: false }) instanceof Promise);
+      assert.ok(marked.parse('test') instanceof Promise);
+    });
+
+    it('should throw an if async is set by extension and a different async parameter is set', () => {
+      marked.use({ async: true });
+
+      assert.throws(() => marked.parse('test', { async: false }), /The async option was set to true by an extension/);
+    });
+
+    it('should not throw an if async is set by extension and a different async parameter is set and the silent parameter is set', () => {
+      marked.use({ async: true });
+
+      assert.doesNotThrow(() => marked.parse('test', { async: false, silent: true }), /The async option was set to true by an extension/);
+    });
+
+    it('should return a Promise if async is set by extension and a different async parameter is set and the silent parameter is set', () => {
+      marked.use({ async: true });
+
+      assert.ok(marked.parse('test', { async: false, silent: true }) instanceof Promise);
     });
 
     it('should allow deleting/editing tokens', () => {