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Last active October 2, 2015 11:49
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file Size Unit Calculator
Raw
README.md

This is a function to calculate the appropriate unit to describe a file size. If you want a fancier function, try this function: https://gist.github.com/2202887 by @vitronprince

Thanks to maettig for minification tips.

Raw
annotated.js
function(
a, //number
c //placeholder
)
{
for(;a>>10;c=-~c)a>>=10; //as long the number is over 1023, divide it by 1024
//a>>10 is the same as a/1024 (Thanks maettig!)
//also set a counter to +1
return a+(" kMGT"[c]||"")+"B"} //return final number + the suffix
Raw
index.js
function(a,c){for(;a>>10;c=-~c)a>>=10;return a+(" kMGT"[c]||"")+"B"}
Shorter version using proper unicode unit symbols:
function(a,c){for(;a>>10;c=-~c)a>>=10;return a+(" ㎅㎆㎇"[c]||"B")}
Raw
package.json
{
"name": "fileSizeUnits",
"description": "Function to calculate the appropriate unit to describe a file size",
"keywords": [
"file",
"size",
"units",
"math"
]
}
Raw
test.html
<!DOCTYPE html>
<title>file Size Unit Calculator</title>
<div>Expected value: <b>269MB</b></div>
<div>Actual value: <b id="ret"></b></div>
<script>
var fileSizeUnits = function(a,c){for(;a>>10;c=-~c)a>>=10;return a+(" kMGT"[c]||"")+"B"}
document.getElementById( "ret" ).innerHTML = fileSizeUnits(282630144)​
</script>
@maettig
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maettig commented Apr 3, 2012

Yea, but it's |0. It's there because c may be "undefined" and must be converted to "0". You can do the same with ~~c.

Edit: I'm wondering about the space. Is it intended to have a space in "15 B" but not in "15MB"?

@williammalo
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Author

@maettig quote:"I'm wondering about the space. Is it intended to have a space in "15 B" but not in "15MB"?"
Oops! Thats a bug alright, I'll go and fix it. :P
Edit: Fixd!

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