Code to test can be tested ahead of time (if you have a 64x48 OLED like this:

let SCL = NodeMCU.D1;
let SDA = NodeMCU.D2;
I2C1.setup({scl:SCL,sda:SDA});
var g = require("https://raw.githubusercontent.com/thedamian/EspruinoDocs/master/devices/SSD1306.js").connect(I2C1,start, { height : 48, width:64 });

Thanks!

It looks like what happened with whitespace is every line is padded with an extra space...

Does it work on your heltec if you specify { width:128, height : 32 }? It seems that width=128 is specified, flipCmds ends up at 0x21,128,127 rather than 0x21,0,127 which is what it was before.

Please could you try this and see if it works? If so I'd feel happier putting it in.

      flipCmds[1] = options.width < 128 ? options.width/2 : 0; // 0x20 for 64, 0 for 128;
      flipCmds[2] = flipCmds[1]+options.width-1; // 0x5f for 64, 127 for 128;

Too bad with the white spaces, it is really hard to see what has changed. As for the computation of flipCmds[1] I think it is too simple because 64 looks like easy case - 128/2. There is SSSD1306 display with width of 72 - there it would fail. At least with that display the right computation is (128-options.width)/2 =28 as visible memory is in the middle from 28 to 99. And BTW that would work for original value of 128 too since (128-128)/2=0.

You can always add ?w=1 to the github diff to turn off whitespace, but I'll indent back in before merging anyway.

The centering sounds good. So you could try:

flipCmds[1] = (128-options.width)/2; // 0x20 for 64, 0 for 128;
flipCmds[2] = flipCmds[1]+options.width-1; // 0x5f for 64, 127 for 128;

Here's a quick link to see the difference without the whitespace as gordon suggests:
https://github.com/espruino/EspruinoDocs/pull/522/files

@gfwilliams I did check the code with my 128x32 screen and it worked, but I will double check later tonight.

Super suggestion by @gfwilliams implemented for cleaner easier to read code

Thanks! Just merged.