Originally posted by reh321 The truth is quite complicated.
The fact is, you won't find any battery charger with a "power in" USB type A port (you will find some with micro-USB type B, and, of course, with type C). You won't be able to charge your laptop through your type C to type A adapter; but you can put an USB stick in there (or connect your phone via a type A to type C (or lightning) cable and charge that - although not at power delivery speeds).
From Wikipedia: "Unlike other data buses (such as Ethernet), USB connections are directed; a host device has "downstream" facing ports that connect to the "upstream" facing ports of devices. Only downstream facing ports provide power; this topology was chosen to easily prevent electrical overloads and damaged equipment. Thus, USB cables have different ends: A and B, with different physical connectors for each".
USB-C is bi-directional, negotiated by the devices. You could even attempt to charge your laptop from your (non-Apple) smartphone though an USB-C to USB-C cable, although that won't do much good!
And this is getting too long. We have the answer that matters.