Benchmark: startsWith vs ===

Script Preparation code:

function get_data (){
const a = [ ], b = [ ] 
for(let i=0; i<1000; ++i)
  {
    const v = Math.random().toPrecision(50)
    a.push(v)
    b.push(v)
  }
  return [a, b]
}

Tests:

a[i].startsWith(b[i]) when a[i] strictly equals b[i]
{ const [a, b] = get_data() const pre = Date.now() let test = true for(let j=0; j<1000; ++j) for(let i=0; i<1000; ++i) test &= a[i].startsWith(b[i]) const post = Date.now() console.log(test === true, post - pre) }
a[i].startsWith(b[j]) when a[i] different than b[j]
{ const [a, b] = get_data() const pre = Date.now() let test = true for(let j=1; j<1000; ++j) for(let i=0; i<1000; ++i) test |= a[i].startsWith(b[j]) const post = Date.now() console.log(test === false, post - pre) }
a[i] === b[i] when a[i] strictly equals b[i]
{ const [a, b] = get_data() const pre = Date.now() let test = true for(let j=0; j<1000; ++j) for(let i=0; i<1000; ++i) test &= a[i] === b[i] const post = Date.now() console.log(test === true, post - pre) }
a[i] === b[j] when a[i] different than b[j]
{ const [a, b] = get_data() const pre = Date.now() let test = true for(let j=1; j<1000; ++j) for(let i=0; i<1000; ++i) test |= a[i] === b[j] const post = Date.now() console.log(test === false, post - pre) }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
a[i].startsWith(b[i]) when a[i] strictly equals b[i]
a[i].startsWith(b[j]) when a[i] different than b[j]
a[i] === b[i] when a[i] strictly equals b[i]
a[i] === b[j] when a[i] different than b[j]

Fastest: N/A

Slowest: N/A

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Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:95.0) Gecko/20100101 Firefox/95.0

Browser/OS: Firefox 95 on Windows

View result in a separate tab

Test name	Executions per second
a[i].startsWith(b[i]) when a[i] strictly equals b[i]	29.0 Ops/sec
a[i].startsWith(b[j]) when a[i] different than b[j]	32.3 Ops/sec
a[i] === b[i] when a[i] strictly equals b[i]	162.3 Ops/sec
a[i] === b[j] when a[i] different than b[j]	40.6 Ops/sec

startsWith vs === (version: 0)

Comparing performance of: a[i].startsWith(b[i]) when a[i] strictly equals b[i] vs a[i].startsWith(b[j]) when a[i] different than b[j] vs a[i] === b[i] when a[i] strictly equals b[i] vs a[i] === b[j] when a[i] different than b[j]

Created: 2 years ago by: Guest

Jump to the latest result

a[i].startsWith(b[i]) when a[i] strictly equals b[i]

a[i].startsWith(b[j]) when a[i] different than b[j]

a[i] === b[i] when a[i] strictly equals b[i]

a[i] === b[j] when a[i] different than b[j]

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A