Methods that read data into byte slices return the number of bytes read. You should save that number and then use it to create your string. If n is the number of bytes read, your code would look like this:
s := string(byteArray[:n])
To convert the full string, this can be used:
s := string(byteArray[:len(byteArray)])
This is equivalent to:
s := string(byteArray[:])
If for some reason you don’t know n, you could use the bytes package to find it, assuming your input doesn’t have a null character embedded in it.
n := bytes.Index(byteArray[:], []byte{0})
Or as icza pointed out, you can use the code below:
n := bytes.IndexByte(byteArray[:], 0)