Same symptoms as on your main webpage:
https://numbrojs.com/format.html#bytes
the spaceSeparated is not doing anything.

In my particular issue:
const size = numbro(x.sizeBytes).format({
spaceSeparated: true,
output: "byte",
base: "decimal",
mantissa: 1
});
return `<tr><td>${x.filename}</td><td>${x.dateModifiedHuman}</td><td>${size}</td><td>${x.md5sum}</td></tr>`;
(apologies, GitHub's 'code' delimiter is Javascript's third type of string literal with escaping operator.
My output string is:

Same symptoms as on your main webpage:
https://numbrojs.com/format.html#bytes
the spaceSeparated is not doing anything.
In my particular issue:
const size = numbro(x.sizeBytes).format({
spaceSeparated: true,
output: "byte",
base: "decimal",
mantissa: 1
});
(apologies, GitHub's 'code' delimiter is Javascript's third type of string literal with escaping operator.
My output string is: