# Banana.SDecimal

##### 在此文中

The Banana.SDecimal (String Decimal) provides functions to do precise decimal math calculation.
It overcomes the rounding problem typical of Javasctipt float type.

Main characteristics:

• use decimal string in the form of '10.00' or '-10' as argument and return value
• '.' is interpreted as the decimal separator
• thousand separator are not allowed
• have up to 34  digits of numeric precision
• do accurate decimal rounding

You can use these functions instead of the javascript Number that uses floating point arithmetic and are not very suitable for accounting calculations due to the rounding differences.

``````

var r = Banana.SDecimal.add('6.50', '3.50');   // return '10.00'
var r = Banana.SDecimal.divide('10', '2');     // return '5.00'
var r = Banana.SDecimal.divide('10', '2', ''); // return '5'
var r = Banana.SDecimal.divide('10', '2');     // return '5.00000'
``````

## Rounding context

Functions can be passed a rounding context that specify the rounding properties:

• decimals is the number of decimal digits (default value is 2)
• null returns the value unrounded.
• '0' returns with no decimals.
• '1' to '33' returns the value with the indicated number of decimals.
• mode is the rounding mode (default value is HALF_UP)
• Banana.SDecimal.HALF_UP the amount is rounded to the nearest. The 0.5 are rounded up.
• Banana.SDecimal.HALF_EVEN the amount is rounded to the nearest. The 0.5 are rounded up or down based on the preceding digit.

If the rounding context is omitted no rounding is done.

### Rounding context of the accounting file

All Banana document files have a rounding context that can be retrieved with the property Banana.document.rounding (see Banana.document).

Examples:

``````

// no context
var r = Banana.SDecimal.divide('10', '3'); // return '3.3333333333333333333333333'

// with context
var context = {'decimals' : 4, 'mode' : Banana.SDecimal.HALF_UP};
var r = Banana.SDecimal.divide('10', '3', context);        // return '3.3333'
var r = Banana.SDecimal.divide('10', '3', {'decimals':0}); // return '3'

// use the rounding property (accunting file 2 decimals)
var r = Banana.SDecimal.divide('10', '3', Banana.document.rounding); // return '3.33'
``````

## Functions

### abs(value1, [, rounding])

Returns the value1 without the sign and rounded as indicated

``````

var r = Banana.SDecimal.abs('-10') // return '10.00'
``````

Returns the sum of value1 and value2.

``````

var r = Banana.SDecimal.add('6.50', '3.50'); // return '10.00'
``````

### compare(value1, value2)

Returns an integer value

• 1 if value1 > value2
• 0 if value1 = value2
• -1 if value1 < value2
``````

Banana.SDecimal.compare('3.50', '2'); // return '1'
Banana.SDecimal.compare('3.00', '3'); // return '0'
``````

### divide(value1, value2 [, rounding])

Returns value1 divided by value2.

``````

var r = Banana.SDecimal.divide('6', '3'); // return '2.00'
``````

### isZero(value)

Returns a boolean

• true if value is zero
• false if value is not zero
``````

var r = Banana.SDecimal.isZero('3.00'); // return 'false'
``````

### max(value1, value2 [, rounding])

Returns the max between value1 and value2.

``````

var r = Banana.SDecimal.max('6', '3'); // return '6.00'
``````

### min(value1, value2 [, rounding])

Returns the min between value1 and value2.

``````

var r = Banana.SDecimal.min('6', '3'); // return '3.00'
``````

### multiply(value1, value2 [, rounding])

Returns value1 multiplied by value2.

``````

var r = Banana.SDecimal.multiply('6', '3'); // return '18.00'
``````

### remainder(value1, value2 [, rounding])

Divide value1 by value2 and returns the reminder.

``````

var r = Banana.SDecimal.reminder('10', '3'); // return '1.00'
``````

### round(value1, [, rounding])

Returns value1 round to the spcified rounding context.

``````

var r = Banana.SDecimal.round('6.123456'); // no context no rounding
r = Banana.SDecimal.round('6.123456', {'decimals':2}); // return '6.12'
``````

### roundNearest(value1, nearest, [, rounding])

Returns value1 round to the specified minimal amount.

``````

var r = Banana.SDecimal.roundNearest('6.17', '0.1'); // return '6.1'
r = Banana.SDecimal.roundNearest('6.17', '0.05', {'decimals':2}); // return '6.15'
``````

### invert(value, [, rounding])

If positive returns a negative value, if negative returns a positive value.

``````

var a = Banana.SDecimal.invert('5'); //return '-5'
var b = Banana.SDecimal.invert('-2.50'); //return '2.50'
``````

### sign(value)

Returns an integer value

• 1 if value > 0
• 0 if  value = 0
• -1 if value < 0
``````

var r = Banana.SDecimal.sign('-5'); // return '-1'
``````

### subtract(value1, value2 [, rounding])

Subtract value2 from value1 and returns the result.

``````

var r = Banana.SDecimal.subtract('10', '3'); // return '7.00'
``````

## Locale conversion

To convert to and from the locale format use the Banana.Converter functions

• Banana.Converter.toInternalNumberFormat(value [, decimals, convZero])
• Banana.Converter.toLocaleNumberFormat(value [, decimalSeparator])
``````

var sum = Banana.SDecimal.add('10000', '2000'); // return '12000.00'
var printValue = Banana.Converter.toLocaleNumberFormat(sum); // return "12'000.00"
``````