oxc/no-optional-chaining

Engines older than ES2020 can't parse ?., so a file that uses it fails to load there. If a compiler lowers it for a target like that, each ?. turns into temporary variables and null and undefined checks, which makes the output larger.

The rule reports each chain once, no matter how many ?. it has.

Configure#

Off by default. To turn it on:

bunfig.toml

[lint.rules]
"oxc/no-optional-chaining" = "error" # or "warn"

Every option, set to its default:

bunfig.toml

[lint.rules]
"oxc/no-optional-chaining" = ["error", {
  message = "", # string
}]

Examples#

example.js1 problem

const city = user?.address?.city;

example.js2 problems

const first = items?.[0];
onSave?.(first);

example.jsNo problems

const city = user && user.address && user.address.city;

if (onSave) {
  onSave(city);
}

Options#

Option	Default	What it does
`message`	`""`	Text to show as help under the report, for example why your project doesn't allow `?.`.

example.jswith { "message": "We ship ES2016 without a compile step." }1 problem

const city = user?.address;

When not to use it#

Every current browser and runtime supports ?.. Only use this rule if your code has to run on older ones.