replace deprecated New Buffer() with Buffer.from()

[harrysarson]

Description of Change

new Buffer() is set to be run time deprecated in node v10 (see nodejs/node#19079 and https://nodejs.org/api/deprecations.html#deprecations_dep0005_buffer_constructor).

I swapped out the usage of new Buffer() for Buffer.from() in mocha's integration tests.

This should be semver patch.

[outsideris]

Mocha still support node.js v4 and Buffer.from is introduced since v5.10.0.
Supporting node v4 will be drop soon.
This PR should be merged after dropping support node v4, I think.

[harrysarson]

@outsideris Buffer.from is already used in mocha. I found it here:

mocha/test/unit/utils.spec.js

Line 165 in 92beda9

expect(stringify(Buffer.from([0x01]))).to.equal('[\n 1\n]');

The tests pass on node 4 even with this change. It seems the buffer.from was actually added in node v4.5 despite what the docs say:

harry@home:~$ nvm use 4.4
Now using node v4.4.7 (npm v2.15.8)
harry@home:~$ node
> Buffer.from('hi')
TypeError: this is not a typed array.
    at Function.from (native)
    at repl:1:8
    at REPLServer.defaultEval (repl.js:262:27)
    at bound (domain.js:287:14)
    at REPLServer.runBound [as eval] (domain.js:300:12)
    at REPLServer.<anonymous> (repl.js:431:12)
    at emitOne (events.js:82:20)
    at REPLServer.emit (events.js:169:7)
    at REPLServer.Interface._onLine (readline.js:211:10)
    at REPLServer.Interface._line (readline.js:550:8)
> .exit
harry@home:~$ nvm use 4.5
Now using node v4.5.0 (npm v2.15.9)
harry@home:~$ node
> Buffer.from('hi')
<Buffer 68 69>

[boneskull]

LGTM. Buffer.from() in v4.x only accepts a single parameter, but it's still present in all v4.x versions.

Netlify failure unrelated.

@harrysarson Thanks!

[outsideris]

@harrysarson My bad. I didn't know that node v4 support Buffer.from.

[harrysarson]

No worries, the node docs are definately unclear about this.

[boneskull]

Yeah, I had to dig into the commit history to figure it out 😝