Run results for: Find the stray v2b

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.100 Safari/537.36

Browser: Chrome 75

Operating system: Mac OS X 10.14.5

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
stray_happy	1793652.0 Ops/sec
stray_heretic	61335.9 Ops/sec
stray_shaye	535139.3 Ops/sec
stray_user	7278276.0 Ops/sec
stray_user_2	3486960.0 Ops/sec
stray_user_3	3383872.0 Ops/sec
stray_user_4	7610990.0 Ops/sec

Script Preparation code:

function stray_happy(numbers) {
  numbers = numbers.sort((a, b) => a - b);
  if (numbers[0] !== numbers[1]) {
    return numbers[0];
  }
  else {
    return numbers[numbers.length - 1];
  }
}


function stray_heretic(numbers) {
  return numbers.find(i => numbers.filter(j => j === i).length === 1);
}


function stray_shaye(numbers) {
  return +numbers.sort((a, b) => a - b)
  	.filter((n,i,a) => (i === 0 && a[0] !==a[1]) || (i === a.length-1 && a[a.length-1] !== a[a.length-2]));
}

function stray_user(a) {
  return a.find(v => a[0] != a[1] ? v != a[2] : v != a[0])
}

function stray_user_2(a) {
	a.find(a[0] != a[1] ? (v, i, a) => v != a[2] : (v, i, a) => v != a[0])
}


function stray_user_3(a) {
    var a0 = a[0], a1 = a[1], a2 = a[2];
	a.find(a0 != a1 ? (v, i, a) => v != a2 : (v, i, a) => v != a0)
}

function stray_user_4(a) {
    var a0 = a[0], a1 = a[1], a2 = a[2];
    if (a0 != a1) a.find((v,i,a) => v != a2);
    else a.find((v,i,a) => v != a0);
}


var numbers = [1,1,1,1,1,1,1,2,1,1,1,1,1,1,1]

Tests:

stray_happy
var n = stray_happy(numbers)
stray_heretic
var n = stray_heretic(numbers)
stray_shaye
var n = stray_shaye(numbers)
stray_user
var n = stray_user(numbers)
stray_user_2
var n = stray_user_2(numbers)
stray_user_3
var n = stray_user_3(numbers)
stray_user_4
var n = stray_user_4(numbers)