Javascript human readable byte size function

March 31, 2020

Here is a small function which converts a bytes in to a readable format (B, KB, MB, GB, TB).

Function

const TB = 1000000000000;
const GB = 1000000000;
const MB = 1000000;
const KB = 1000;

function bytesReadable(byteSize, decimals) {
    let unit;
    let i;
    let remainder;

    // Get the whole number, and the remainder for the
    // decimals later on.
    if (byteSize > TB) {
        unit = "TB";
        i = Math.floor(byteSize / TB);
        remainder = byteSize - (i * TB);
    }else if (byteSize > GB) {
        unit = "GB";
        i = Math.floor(byteSize / GB);
        remainder = byteSize - (i * GB);
    }else if (byteSize > MB) {
        unit = "MB";
        i = Math.floor(byteSize / MB);
        remainder = byteSize - (i * MB);

    }else if (byteSize > KB){
        unit = "KB";
        i = Math.floor(byteSize / KB),
            remainder = byteSize - i * KB;
    }else{
        // Can't go smaller than bytes!
        return i.toString() + " " + unit;
    }

    if (decimals === 0){
        return i.toString() + " " + unit;
    }

    // Now we calculate the eventual missing leading
    // zeroes to pad up if needed.
    let width;
    if (remainder > GB){
        width = 12;
    }else if (remainder > MB){
        width = 9;
    }else if (remainder > KB){
        width = 6;
    }else{
        width = 3;
    }

    // Fill up leading zeroes if they are missing
    let remainderString = remainder.toString();

    for (let i = remainderString.length; i < width; i++){
        remainderString = "0" + remainderString;
    }

    // Check to prevent unwanted behaviour
    if (decimals > remainderString.length){
        decimals = remainderString.length;
    }

    return i.toString() + "." + remainderString.substr(0, decimals) + " " + unit;
}

Sample

console.log(bytesReadable(425005, 2));
console.log(bytesReadable(8741208, 2));
console.log(bytesReadable(114448910, 2));
console.log(bytesReadable(557891, 2));
console.log(bytesReadable(114710, 2));
console.log(bytesReadable(8933578, 2));
console.log(bytesReadable(5849684981, 2));
console.log(bytesReadable(12033687, 2));
console.log(bytesReadable(742289, 2));
console.log(bytesReadable(678007439, 2));

// Output
425.00 KB
  8.74 MB
114.44 MB
557.89 KB
114.71 KB
  8.93 MB
  5.84 GB
 12.03 MB
742.28 KB
678.00 MB

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Golang human readable byte sizes

March 31, 2020

Here is a function that prints out byte sizes, like the return from len() function, into human readable units.

Function and example

package main

import (
	"fmt"
	"strconv"
)

const (
	TB = 1000000000000
	GB = 1000000000
	MB = 1000000
	KB = 1000
)

func lenReadable(length int, decimals int) (out string) {
	var unit string
	var i int
	var remainder int

	// Get whole number, and the remainder for decimals
	if length > TB {
		unit = "TB"
		i = length / TB
		remainder = length - (i * TB)
	} else if length > GB {
		unit = "GB"
		i = length / GB
		remainder = length - (i * GB)
	} else if length > MB {
		unit = "MB"
		i = length / MB
		remainder = length - (i * MB)
	} else if length > KB {
		unit = "KB"
		i = length / KB
		remainder = length - (i * KB)
	} else {
		return strconv.Itoa(length) + " B"
	}

	if decimals == 0 {
		return strconv.Itoa(i) + " " + unit
	}

	// This is to calculate missing leading zeroes
	width := 0
	if remainder > GB {
		width = 12
	} else if remainder > MB {
		width = 9
	} else if remainder > KB {
		width = 6
	} else {
		width = 3
	}

	// Insert missing leading zeroes
	remainderString := strconv.Itoa(remainder)
	for iter := len(remainderString); iter < width; iter++ {
		remainderString = "0" + remainderString
	}
	if decimals > len(remainderString) {
		decimals = len(remainderString)
	}

	return fmt.Sprintf("%d.%s %s", i, remainderString[:decimals], unit)
}

func main() {
	test := []int{425005, 8741208, 114448910, 557891, 557,
		114710, 8933578, 5849684981, 12033687, 742289, 678007439}

	for _, v := range test {
		fmt.Println(v, "\t = ", lenReadable(v, 2))
	}
}

Output

425005          =  425.00 KB
8741208         =  8.74 MB
114448910       =  114.44 MB
557891          =  557.89 KB
557             =  557 B
114710          =  114.71 KB
8933578         =  8.93 MB
5849684981      =  5.84 GB
12033687        =  12.03 MB
742289          =  742.28 KB
678007439       =  678.00 MB

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Golang creating a worker thread pool using maps

July 24, 2016

This example will show you how to create a worker thread that waits for jobs and working them one by one. We use maps to create a list where we add jobs too. This tutorial will process strings and create bcrypt hashes of it, for simulating purposes.

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