Enforce `Buffer.from` instead of `new Buffer` about eslint-plugin-unicorn

[SamVerschueren]

I want to take this one if that's ok?

[jfmengels]

ESLint can't target specific Node.js versions, right?

You're right, it can't.

Not sure if it makes sense to already create this rule

Well, it can be useful for people who will only target Node >= 6 versions for their app/libraries, so I'd say yes.

I wonder, are there any other similar constructs where new XYZ() is replaced by a method on XYZ? I don't know if it would make sense to generalize this.

[sindresorhus]

Buffer.from() was backported to Node.js 4 (benefits of it being LTS), so we can safely enforce it.

[kevva]

Buffer.from() was backported to Node.js 4 (benefits of it being LTS), so we can safely enforce it.

Oh, didn't know that. Nice!

[sindresorhus]

@SamVerschueren Go ahead 🤘

[jfmengels]

I wonder, are there any other similar constructs where new XYZ() is replaced by a method on XYZ? I don't know if it would make sense to generalize this.

So this will be a rule specific to Buffer then?

[sindresorhus]

@jfmengels Yes. We can add a more generic rule in the future if use-cases come up.

[SamVerschueren]

So this will be a rule specific to Buffer then?

Exactly, no need to add a "complex construct" which might never get used. We can always improve later on.

[jfmengels]

Okay, sounds good to me.

[kevva]

Make sure to take Buffer.alloc() into account too. See kevva/to-ico@22b4472.

[SamVerschueren]

Aha, good catch @kevva. It's not as simple as finding a NewStatement with Buffer and changing that to Buffer.from().

[niksy]

Just wanted to point out that eslint-plugin-node has similar rule for deprecated APIs if you need some hints on how to additionally approach this: https://github.com/mysticatea/eslint-plugin-node/blob/master/docs/rules/no-deprecated-api.md

[SamVerschueren]

How should we call this rule?

• no-new-buffer
• new-buffer-deprecated
• buffer-deprecated
• ...

[sindresorhus]

@SamVerschueren no-new-buffer

[SamVerschueren]

Should we also cover the case that someone could write this? It works perfectly although XO will fail with the new-cap rule.

const buf = Buffer('foo');

[sindresorhus]

Nah, I've never seen anyone write that, and as you said, it's already covered by the new-cap rule.