headache.js

// Expectation: [1, 8, 6, 4, 3, 5, 7, 2]

var teams = [1, 2, 3, 4, 5, 6, 7, 8];
var matches = [];

for(var pos = 0; pos < teams.length / 2; pos++)
{
   var even = pos % 2 === 0;
   var ta = teams[pos];
   var tb = teams[(teams.length - 1) - pos];
   
   matches.push(even ? ta : tb);
   matches.push(even ? tb : ta);
}

console.log(matches);

// got: [1, 8, 7, 2, 3, 6, 5, 4]
// exp: [1, 8, 6, 4, 3, 5, 7, 2] =(