unexpected use of comma using map on a object

I'm using the AirBnb style guide and get an "unexpected use of comma" error here at the end of the first line of code:

  myApp.fields.map(field => (field.obj.label = field.label.default,
    field.label.textContent = field.obj.label));

I can rewrite it to this to remove the error:

  myApp.fields.map(field => field.obj.label = field.label.default);
  myApp.fields.map(field => field.label.textContent = field.obj.label);

https://eslint.org/docs/rules/no-sequences

The way I see the first bit of code that the map loop only runs once of the fields where the second one runs twice.

I can confirm that both parts of the map above are executing and not just the last one. Is there something else I'm missing?

Since you're not transforming the array, you could just use forEach() instead of map(). If you insist on making it into a one-liner, and don't want to violate the no-sequences rule:

myApp.fields.forEach(field => {field.obj.label = field.label.default; field.label.textContent = field.obj.label});

More readable:

myApp.fields.forEach((field) => {
    field.obj.label = field.label.default;
    field.label.textContent = field.obj.label;
});