object?.method?.() is equivalent to if(object && object.method) object.method(), not if(object) object.method(). I think we should not add extra checks to avoid behaviour changes, and it might impact perf.

Yes, thanks for the guidance.

Benchmark run (link may not yet be active): https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/760/

Nevermind.. looks like @mscdex beat me to it. There was a benchmark job running already but I hadn't noticed that it was for the same PR.

https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/759/

CI: https://ci.nodejs.org/job/node-test-pull-request/34964/

Performance benchmark results look good! Happy to see us start to make these changes. The one downside is that it'll make backporting a bit more difficult

Yes, and this will make our code easier to read. And I have two questions and would like to know what you think.

1. I noticed that there are many modules that can be converted to optional chaining.Should we modify multiple modules in a single Pull Request?

2. You mentioned that this make backporting a bit more difficult, should we stop such work for now?

Incremental changes are best. And no, backporting shouldn't hold this up.

Incremental changes are best. And no, backporting shouldn't hold this up.

I know what to do now, thanks for your guidance.

Yes, and this will make our code easier to read.

I disagree :)

Yes, and this will make our code easier to read.

I disagree :)

When there is a difference of opinion on code style, I think we should look at what the community thinks.

TypeScript Pull Request (Add support for Optional Chaining):
microsoft/TypeScript#33294

Reference: MDN

This results in shorter and simpler expressions when accessing chained properties when the possibility exists that a reference may be missing.

Reference: V8: Optional chaining

// Error prone-version, could throw.
const nameLength = db.user.name.length;

// Less error-prone, but harder to read.
let nameLength;
if (db && db.user && db.user.name)
  nameLength = db.user.name.length;

// The above can also be expressed using the ternary operator, which doesn’t exactly help readability
const nameLength =
  (db
    ? (db.user
      ? (db.user.name
        ? db.user.name.length
        : undefined)
      : undefined)
    : undefined);

// Still checks for errors and is much more readable.
const nameLength = db?.user?.name?.length;

Landed in 54e763d