Merge pull request #593 from marp-team/new-headless-mode

Adopt new headless mode by default

CHANGELOG.md

@@ -8,6 +8,8 @@
 - Upgrade Marp Core to [v4.0.0](https://github.com/marp-team/marp-core/releases/v4.0.0) ([#591](https://github.com/marp-team/marp-cli/pull/591))
   - The slide container of built-in themes became the block element and adopted safe centering
   - Relax HTML allowlist: Allowed a lot of HTML elements and attributes by default
+- Use [the new headless mode of Chrome](https://developer.chrome.com/docs/chromium/headless) while converting by default ([#593](https://github.com/marp-team/marp-cli/pull/593))
+  - You can get back to the old headless mode by setting `PUPPETEER_HEADLESS_MODE=old` env.
 
 ### Added
 

src/utils/puppeteer.ts

@@ -15,7 +15,11 @@ let executablePath: string | undefined | false = false
 let wslTmp: string | undefined
 
 export const enableHeadless = (): 'shell' | true =>
-  process.env.PUPPETEER_HEADLESS_MODE?.toLowerCase() === 'new' ? true : 'shell'
+  ['old', 'legacy', 'shell'].includes(
+    process.env.PUPPETEER_HEADLESS_MODE?.toLowerCase() ?? ''
+  )
+    ? 'shell'
+    : true
 
 const isShebang = (path: string) => {
   let fd: number | null = null

test/utils/puppeteer.ts

@@ -201,14 +201,14 @@ describe('#generatePuppeteerLaunchArgs', () => {
   })
 
   describe('with PUPPETEER_HEADLESS_MODE env', () => {
-    it('uses legacy headless mode if PUPPETEER_HEADLESS_MODE was empty', async () => {
+    it('uses headless mode if PUPPETEER_HEADLESS_MODE was empty', async () => {
       try {
         process.env.PUPPETEER_HEADLESS_MODE = ''
 
         const { headless } =
           await puppeteerUtils().generatePuppeteerLaunchArgs()
 
-        expect(headless).toBe('shell')
+        expect(headless).toBe(true)
       } finally {
         delete process.env.PUPPETEER_HEADLESS_MODE
       }
@@ -252,6 +252,19 @@ describe('#generatePuppeteerLaunchArgs', () => {
         delete process.env.PUPPETEER_HEADLESS_MODE
       }
     })
+
+    it('uses legacy headless mode if PUPPETEER_HEADLESS_MODE was "shell"', async () => {
+      try {
+        process.env.PUPPETEER_HEADLESS_MODE = 'shell'
+
+        const { headless } =
+          await puppeteerUtils().generatePuppeteerLaunchArgs()
+
+        expect(headless).toBe('shell')
+      } finally {
+        delete process.env.PUPPETEER_HEADLESS_MODE
+      }
+    })
   })
 
   describe('with CHROME_PATH env in macOS', () => {