File size display in file browser should use correct units

[msanchezst]

Problem

We have noticed that the file size displayed in the Jupyterlab file browser appears to be using an incorrect unit. The file sizes are reported in MiB but the displayed units are MB,GB, and so on. This is confusing as the actual size is not accurately represented.

Proposed Solution

I would recommend updating the file browser to display the file sizes using the correct units (MiB) to match the actual file sizes reported by the OS.

In the screenshot above, the units displayed in the File Explorer should be MiB

Additional context

Has this issue been evaluated in the past and decided to report the file sizes in this way? If so, I'm curious to understand the reasoning behind that decision.

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[krassowski]

Quick look: I think that the file manager in jupyter-server by default returns size in bytes, based on this code referencing st_size which normally is in bytes.

Then on frontend this is formatted here

jupyterlab/packages/filebrowser/src/listing.ts

Lines 2695 to 2700 in b3f0b44

	const fileSizeText = Private.formatFileSize(model.size, 1, 1024);
	fileSize.textContent = fileSizeText;
	hoverText += trans.__(
	'\nSize: %1',
	Private.formatFileSize(model.size, 1, 1024)
	);

Using this function:

jupyterlab/packages/filebrowser/src/listing.ts

Lines 3007 to 3027 in b3f0b44

	/**
	* Format bytes to human readable string.
	*/
	export function formatFileSize(
	bytes: number,
	decimalPoint: number,
	k: number
	): string {
	// https://www.codexworld.com/how-to/convert-file-size-bytes-kb-mb-gb-javascript/
	if (bytes === 0) {
	return '0 B';
	}
	const dm = decimalPoint || 2;
	const sizes = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
	const i = Math.floor(Math.log(bytes) / Math.log(k));
	if (i >= 0 && i < sizes.length) {
	return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + ' ' + sizes[i];
	} else {
	return String(bytes);
	}
	}

[krassowski]

Does it make more sense to show MiB vs MB? What do most file browsers show? Real-estate-wise MB is shorter. Should it be configurable?

[msanchezst]

@krassowski thank you for your quick response! Based on this:

jupyterlab/packages/filebrowser/src/listing.ts

Lines 2695 to 2700 in b3f0b44

	const fileSizeText = Private.formatFileSize(model.size, 1, 1024);
	fileSize.textContent = fileSizeText;
	hoverText += trans.__(
	'\nSize: %1',
	Private.formatFileSize(model.size, 1, 1024)
	);

it looks to me that because of the value of 1024 set in the formatFileSize, the formatted file size is converted to Bi Units (KiB,MiB,GiB), but the labels here are incorrect:

jupyterlab/packages/filebrowser/src/listing.ts

Line 3020 in b3f0b44

const sizes = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];

As for what units to display, that's a good question. Mac and Windows file browsers typically use MB. Some Linux file browsers let you change the units. Technically, MiB might be more accurate, but I don't think there is a established standard here. Perhaps making this configurable would be the best approach?