Many Codecov responses include a totals object. The format of this object is outlined below.

{
  "totals": {
    "c": "70.00000",  // coverage ratio
    "f": 2,               // files count
    "n": 10,          // lines count
    "h": 7,           // hits count
    "m": 2,           // missed count
    "p": 1,           // partials count
    "b": 3,           // branches count
    "d": 0,           // methods count
    "M": 0,           // messages count
    "s": 3            // sessions count
  }
}

In the case of comparing commits, a diff array may also be returned, It is defined as follows:

"diff": [
1,                  //files count
0,                  //lines count
0,                  //hits count
0,                  //misses count
0,                  //partials count
null,                   //coverage (null or number)
0,                  //branches count
0,                  //methods count
0,                  //messages count
0,                  //sessions count
null,                   //complexity (null or number)
null,                   //complexity_total (null or number)
,0],                //diff

The coverage, complexity, and complexity_total values will be null if the diff contains a lines count of zero.