Run results for: Date JsonReviver8

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.84 Safari/537.36

Browser: Chrome 99

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Baseline	31.6 Ops/sec
Regex	26.3 Ops/sec
No check	29.3 Ops/sec
Length	32.0 Ops/sec

Script Preparation code:

var input = [];

for (i = 2; i <= 100000; i++) {
    const date = new Date(Math.random()*1000);
  
    const value = i % 2 === 0 ? date.toISOString() : 'some random value';
    const key = i % 2 === 0 ? 'businessDate' : 'some random key';
  
    input.push({
        key,
        value
    });
  
    input.push({
        key: 'index',
        value: i
    });
  
  input.push({
        key: 'updatedAt',
        value: i
    });
  
  input.push({
        key: 'a',
        value: Math.random()
    });
  
  input.push({
        key: 'b',
        value: Math.random()
    });
  
    input.push({
        key: 'c',
        value: Math.random()
    });
  
  input.push({
        key: 'd',
        value: Math.random()
    });
  
  input.push({
        key: 'e',
        value: Math.random()
    });
}

Tests:

Baseline
const result = input.map(x=>{ if (typeof x.value !== 'string') { return x.value; } switch (x.key) { case 'businessDate': case 'startDate': case 'endDate': case 'createdAt': case 'updatedAt': return new Date(x.value); default: return x.value; } });
Regex
const result = input.map(x=>{ if (typeof x.value !== 'string') { return x.value; } switch (x.key) { case 'businessDate': case 'startDate': case 'endDate': if (/(\d{4})-(\d{2})-(\d{2})/.test(x.value)) { return new Date(x.value + 'T00:00:00.000'); } return new Date(x.value); case 'createdAt': case 'updatedAt': return new Date(x.value); default: return x.value; } });
No check
const result = input.map(x=>{ if (typeof x.value !== 'string') { return x.value; } switch (x.key) { case 'businessDate': case 'startDate': case 'endDate': return new Date(x.value + 'T00:00:00.000'); case 'createdAt': case 'updatedAt': return new Date(x.value); default: return x.value; } });
Length
const result = input.map(x=>{ if (typeof x.value !== 'string') { return x.value; } switch (x.key) { case 'businessDate': case 'startDate': case 'endDate': if (x.value.length === 10) { return new Date(x.value + 'T00:00:00.000'); } return new Date(x.value); case 'createdAt': case 'updatedAt': return new Date(x.value); default: return x.value; } });

Run results for: Date JsonReviver8

Baseline

Regex

No check

Length