size-rate

Format current and maximum bytes into a human-readable expression

const SizeRate = require('size-rate');

const sizeRate = SizeRate({max: 100_000_000});

sizeRate.format();
//=> '  0.00 MB / 100.00 MB'

sizeRate.set(75_049_821);

sizeRate.format();
//=> ' 75.05 MB / 100.00 MB'

sizeRate.set(100_000_000);

sizeRate.format(100_000_000);
//=> '100.00 MB / 100.00 MB'

This module is useful for printing progress to the same line with process.stdout.clearLine().

The format is designed to keep initial string length: it adds whitespaces to short values, keeps using the same unit and number of decimal spaces regardless of the current value.

Usually, without string length unification, you ought to get more restless output instead.

Installation

Use npm.

npm install size-rate

API

const SizeRate = require('size-rate');

class SizeRate(options)

options: Object
Return: Object

options

Options are directly passed to filesize.js with these differences:

• base option defaults to 10 instead of 2.
• standard option defaults to iec.
• exponent, fullform, fullforms and output options are not supported.

Also you need to set the following option:

max

Type: number (non-negative finite integer)

Required. The maximum size in byte displayed as a denominator.

Instance properties

max

Type: number

The maximum size. Same as the max property passed to the constructor.

bytes

Type: number

The current size.

formatLength

Type: number

Length of a string format() method returns.

Instance methods

format()

Return: string

Create a string in the form ${bytes} ${unit_of_max} / ${max} ${unit_of_max} using bytes and max properties.

new SizeRate({max: 1024}).format();
//=> '0.00 kB / 1.02 kB'

new SizeRate({max: 1024, base: 2}).format();
//=> '0.00 KiB / 1.00 KiB'

set(currentBytes)

currentBytes: integer (non-negative finite integer)

Set the current size in byte displayed as a numerator.

const sizeRate = new SizeRate({max: 300_000_000, round: 1});

sizeRate.format();
//=> '  0.0 MB / 300.0 MB'

sizeRate.set(123_456_789);

sizeRate.format();
//=> '123.5 MB / 300.0 MB'

Note that the argument must not be larger than max property.

const sizeRate = new SizeRate({max: 10});

sizeRate.set(11);
// RangeError: Expected a number no larger than the max bytes (10), but got 11.

format(currentBytes)

currentBytes: integer (non-negative finite integer)
Return: string

Call set() method with a given argument, then call format() method.

const sizeRate = new SizeRate({max: 7000, base: 2});

// Same as sizeRate.set(500); sizeRate.format()
sizeRate.format(500);
//=> '0.49 KiB / 6.84 KiB'

sizeRate.bytes;
//=> 500

License

ISC License © 2018 - 2019 Watanabe Shinnosuke