Перемещение элемента массива в начало

var arr = [0, 1, 2, 3, 4, 5] 
arr.unshift(...arr.splice(3,1)); 
console.log(arr);

var arr = [0, 1, 2, 3, 4, 5]; 
var value = 3; 
 
arr.sort(function(x,y){  
  return x == value ? -1 : y == value ? 1 : 0;  
}); 
 
console.log(arr);

var arr = [0, 1, 2, 3, 4, 5]; 
var index = 3; 
 
arr.splice(0, 0, arr.splice(index, 1)[0]); 
 
console.log(arr);

var a = [0, 1, 2, 3, 4, 5]; 
console.log(a); 
var b = [a[3]].concat(a.slice(0, 3), a.slice(4)) 
console.log(b);

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