Concat several arrays in JavaScript (nodejs)

Question

What would be the more concise way to concat all ar arrays in the following object:

var obj = {
  field1: {
    ar: [...]
  },
  field2: {
    ar: [...]
  },
  ...
  fieldN: {
    ar: [...]
  }
}

I found this:

Object.keys(obj).reduce(function(array, entry) {
  return array.concat(obj[entry].files);
}, []);

Answer 1

您可以这样尝试：

[].concat.apply([], [array1, array2, ...])