The code checks if the value of `o.meses` is not...

The code checks if the value of o.meses is not present in the mes array. If it is not present, the code performs the following actions:

1. It adds a new key-value pair to the mes object with the key as o.meses and the value as the index returned from the push method when adding o.meses to the data.labels array minus one.
2. It loops through each dataset in the data.datasets array using the forEach method and adds a zero value to its data array.