In your browser, you may easily separate or combine files using a binary data buffer (ArrayBuffer)!
"Binary Splitting & Merging" is a browser plugin that allows you to split a file into several smaller parts (chunks). You can also use the merge feature to combine diverse file pieces together to create a single file.
To use this extension, drag and drop a file into the app's UI (bottom section). Then adjust the desired number of chunks (or desired segment size) and then click on the - Split - Download - button. Similarly, to combine small file portions, drag and drop file segments in the app UI, change the final file type and extension, and then click on the - Merge & Download - button.