How to specify browser language in Puppeteer

Question

I would like to launch a Google Chrome browser with language Spanish es using Puppeteer.

I've tried puppeteer.launch(args:['--lang=es',...],...) but it didn't work.

I've tried passing the environment variable LANGUAGE=es mocha puppeteer-test.js but it didn't work.

I've tried using the userDataDir option and passing a folder with a Preferences file a { "intl": { "accept_languages": "es" } } but the browser Settings - Languages still don't show Spanish and neither does window.navigator.languages neither window.navigator.language

I'm using
Puppeteer 0.11.0
Node 8.4.0
NPM 5.2.0
macOS El Capitan 10.11.6
MacBook Pro Retina, 15-inch, Mid 2015

Solution 1

There are several ways to change locale, you can try all of them to find what works for you,

Use Args when launching

const browser = await puppeteer.launch({
    headless: false,
    args: ['--lang=bn-BD,bn']
});

Send the language as Header

await page.setExtraHTTPHeaders({
    'Accept-Language': 'bn'
});

Forcefully set the language

// Set the language forcefully on javascript
await page.evaluateOnNewDocument(() => {
    Object.defineProperty(navigator, "language", {
        get: function() {
            return "bn-BD";
        }
    });
    Object.defineProperty(navigator, "languages", {
        get: function() {
            return ["bn-BD", "bn"];
        }
    });
});

For the sake of testing, I'll test this in multiple languages, including es, and here is the result.

Google search:

BrowserLeaks:

Solution 2

There's an error in Md-Abu-Taher's answer.

The response to navigator.language should return a string, not an array. Try it in your own browser console.

The code snippet should be:

await page.evaluateOnNewDocument(() => {
    Object.defineProperty(navigator, "language", {
        get: function() {
            return "en-GB";
        }
    });
    Object.defineProperty(navigator, "languages", {
        get: function() {
            return ["en-GB", "en"];
        }
    });
});

Comments

[avalanche1]

Mind you, that args solution doesnt work on mac os

[Aaron]

Is there another way for mac OS X?

[Md. Abu Taher]

Thank you for pointing that out, I've updated my answer.

[Petr Bodnár]

At Chromium issue 755338 they write that setting environment variable LANG should work as well on Linux. Nothing like that for Windows though, it seems...