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up vote 8 down vote favorite

What's the best way to format a number?

  • If decimal is less than 2 digits, add zero to make it 2 decimals
  • If more than 4, truncate to 4 decimals

  • If 3 decimals, keep it to 3 decimals

    14 => 14.00
14.1 => 14.10
14.123 => 14.123
14.12347 => 14.1234

I don't want rounding to happen

if (number !== 0) {
    nParts = number.toString().split('.');
    if (nParts[1]) {
      if (nParts[1].length > 4) {
        nParts = 4;
      } else if (nParts[1].length < 3) {
        nParts = 2;
      } else {
        nParts = 3;
      }
    } else {
      nParts = 2;
    }
} 
number = number.toFixed(nParts);

Help me improve on this.

share|improve this question
    
Just to clarify - you don't want the extra decimals to round, you want to cut them off, right? –  kleinfreund Jan 26 at 14:54
2  
As I interpret it, 14.99999 → '14.9999' –  200_success♦ Jan 26 at 17:53
2  
toString().split('.') isn't going to work reliably. Consider that some cultures write their numbers using a comma for a decimal 987,24 –  George Mauer Jan 27 at 1:39
    
@kleinfreund Right –  Vjy Jan 27 at 13:04
    
@200_success Correct –  Vjy Jan 27 at 13:05
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1 Answer

up vote 2 down vote accepted

since you don't want rounding, treat as string rather than number... 

function strange(number){
    var n=0;
    if (number !== 0) {
        nParts = number.toString().split(/\.|,/);
        if (nParts[1]){
            n=nParts[1].length;
            n = n <=2 ? 2 : n==3 ? 3 : 4;
            nParts[1] = nParts[1] + '0'
        }else{
            n=2;
            nParts[1]='00';
        }
    } 
    return nParts[0] + '.' + nParts[1].slice(0,n);
}

;strange(14);
;strange(14.1);
;strange(14.123);
;strange(14.12347);

/*
14 => 14.00
14.1 => 14.10
14.123 => 14.123
14.12347 => 14.1234
*/
share|improve this answer
    
Perfect, will try this now. Thanks –  Vjy Jan 27 at 13:06
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