Run results for: Normal vs ?.

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.63 Safari/537.36

Browser: Chrome 93

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Normal	319.8 Ops/sec
Use ?. syntax	319.2 Ops/sec

Script Preparation code:

function mitt(e) {
    return {
        all: e = e || new Map,
        on: function(n, t) {
            var f = e.get(n);
            f ? f.push(t) : e.set(n, [t])
        },
        off: function(n, t) {
            var f = e.get(n);
            f && (t ? f.splice(f.indexOf(t) >>> 0, 1) : e.set(n, []))
        },
        emit: function(n, t) {
            var f = e.get(n);
            f && f.slice().map(function(e) {
                e(t)
            }), (f = e.get("*")) && f.slice().map(function(e) {
                e(n, t)
            })
        }
    }
}

var emitter = mitt()

emitter.on("create:dir", path => console.log(`Created dir at ${path}`))

Tests:

Normal
for ( let i = 0; i < 50; i++ ) { emitter?.emit("create:dir", "/"); }
Use ?. syntax
for ( let i = 0; i < 50; i++ ) { emitter.emit("create:dir", "/"); }

Run results for: Normal vs ?.

Normal

Use ?. syntax