How to know if Metamask is already installed?

[Tedko]

Right now finished the integration. however within our extension we have no idea whether user install MetaMask already or not. @danfinlay any good idea? Many thanks

[brad-decker]

I would recommend using our onboarding library for these purposes. Examples can be seen here

[Tedko]

Hi @brad-decker .

We already noticed onboarding library. However Metamask cannot inject js into another extension's page ( something like chrome-extension://jkoeaghipilijlahjplgbfiocjhldnap/index.html#/wallets )

That's why we're wondering if there's any solution.

[Tedko]

injecting js into another extension's page is not allowed by browser. There're other browser APIs could do so (some communication between extensions)

Right now we already able to use MetaMask inside Maskbook extension, and then provide MetaMask func on fb/Twitter. The only problem is within the extension's html page we don't know whether users installed Maskbook or not

[Jack-Works]

I'm afraid the onboarding library doesn't work for another web extension.

https://github.com/MetaMask/metamask-onboarding/blob/master/src/index.ts#L154

In this line, you detect metamask by window.ethereum.isMetaMask but window.ethereum is not available in the web extension. This is why I'm using extension-provider`(this library)

[Tedko]

Hi @brad-decker - any thoughts?

[neruthes]

I have been wondering whether this way is going to work.

If MetaMask is installed:

• The user clicks "Link a MetaMask Wallet" button.
• Maskbook opens URL "https://maskbook.com/webext-bridge/metamask.html" in a new tab.
• MetaMask injects some object on window.
• Maskbook reads the injected object on window.
• Maskbook knows that MetaMask is installed.
• Maskbook sends requests to MetaMask through the webpage.

If MetaMask is not installed:

• (Shared initial steps)
• Maskbook fails reading the injected object on window.
• Maskbook lets the webpage know the failure.
• The webpage suggests the user to install MetaMask with a proper browser-specific extension store link.

[danfinlay]

You should also be able to detect whether MetaMask is installed using the error event we have on this library's provider:

const createMetaMaskProvider = require('metamask-extension-provider')

const provider = createMetaMaskProvider()

provider.on('error', (error) => {
  // Failed to connect to MetaMask, likely MetaMask is not installed.
})

[Tedko]

@danfinlay thx it seems working well now :) @Jack-Works should we close this? would be great if you can make a document of this @danfinlay

[Jack-Works]

Yeah I think we can close this now

[Tedko]

🎭 Thx for all 🦊❤️