three.js/test/treeshake/utils/format-size.js

// used in report-size.yml

export function formatBytes( bytes, decimals = 1 ) {

	if ( bytes === 0 ) return '0 B';

	const k = 1000;
	const dm = decimals < 0 ? 0 : decimals;
	const sizes = [ 'B', 'kB', 'MB', 'GB' ];

	const i = Math.floor( Math.log( bytes ) / Math.log( k ) );

	return parseFloat( ( bytes / Math.pow( k, i ) ).toFixed( dm ) ) + ' ' + sizes[ i ];

}

const n = Number( process.argv[ 2 ] );
const formatted = formatBytes( n );

console.log( formatted );