README
ramda-decimal
Ramda wrapper to Decimal.js
Use Decimal.js arbitrary precision maths in Ramda style. Immutable. Composable. Curry-able.
Drop-in replacements for most Ramda math functions.
const R = require('ramda);
const RD = require('ramda-decimal);
const annualTax = R.pipe(
R.pluck(income),
RD.sum,
RD.times(TAX_RATE),
);
const format = RD.fixed(2);
console.log(format(annualTax(months)));
Liberal inputs, conservative outputs
Like Decimal.js, RD accepts Decimals, number primitives and strings that look like numbers. RD does this by calling new Decimal()
on any input.
All RD functions return Decimal
s.
Constants
ZERO
and ONE
are defined as constants. Use them! They're immutable.
Parameter order
When there is a corresponding Ramda function, RD uses the same parameter order. This does mean that curried relation functions are unintuitive (in my opinion) in the same way as Ramda:
const f = RD.gt(5);
return f(6); // false: gt(5,6)
Where there is no corresponding Ramda function, we have flipped the parameters when it seems useful for point-free coding:
const formatToPennies = RD.toFixed(2);
Currying and efficiency
For brevity the documentation suggests that (for example)
RD.add(a)(b)
is equivalent to new Decimal(a).plus(b)
. The reality is
a bit better than that. RD.add(a)
stores any Decimal
it creates
for reuse. Hence in:
const addTen = RD.add(10);
const n110 = addTen(100);
const n210 = addTen(200);
... new Decimal(10)
is only run once.
Mixed style
Returned values are just Decimal
objects, so you are free to combine styles
if you want to:
const displayTotal = RD.sum(vals).fixed(2, Decimal.ROUND_HALF_UP);
Docs
Modules
- ramda-decimal
Ramda-style curried functions wrapping the methods of Decimal.js
Typedefs
- DecimalLike :
Decimal
|number
|string
A Decimal, number, or a string containing a number. That is, any valid parameter to
new Decimal(...)
ramda-decimal
Ramda-style curried functions wrapping the methods of Decimal.js
Decimal
| number
| string
DecimalLike : A Decimal, number, or a string containing a number.
That is, any valid parameter to new Decimal(...)
Decimal
.abs(n) ⇒ Equivalent to new Decimal(n).absoluteValue()
Kind: static function
Param | Type |
---|---|
n | DecimalLike |
Decimal
.add(a, b) ⇒ Equivalent to new Decimal(a).plus(b)
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
b | DecimalLike |
Decimal
.ceil(n) ⇒ Equivalent to new Decimal(n).ceil()
Kind: static function
Param | Type |
---|---|
n | DecimalLike |
boolean
.eq(a, b) ⇒ Equivalent to new Decimal(a).equals(b)
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
b | DecimalLike |
Decimal
.divide(a, b) ⇒ Equivalent to new Decimal(a).dividedBy(b)
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
b | DecimalLike |
Decimal
.divideBy(a, b) ⇒ Equivalent to new Decimal(b).dividedBy(a)
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
b | DecimalLike |
Decimal
.floor(n) ⇒ Equivalent to new Decimal(n).floor()
Kind: static function
Param | Type |
---|---|
n | DecimalLike |
boolean
.gt(a, b) ⇒ Equivalent to new Decimal(a).gt(b)
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
b | DecimalLike |
boolean
.gte(a, b) ⇒ Equivalent to new Decimal(a).gte(b)
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
b | DecimalLike |
boolean
.lt(a, b) ⇒ Equivalent to new Decimal(a).lt(b)
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
b | DecimalLike |
boolean
.lte(a, b) ⇒ Equivalent to new Decimal(a).lte(b)
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
b | DecimalLike |
Decimal
.multiply(a, b) ⇒ Equivalent to new Decimal(a).times(b)
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
b | DecimalLike |
Decimal
.negate(a) ⇒ Equivalent to new Decimal(a).negated()
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
Decimal
.round(a) ⇒ Equivalent to new Decimal(a).round()
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
Decimal
.subtract(a, b) ⇒ Equivalent to new Decimal(a).minus(b)
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
b | DecimalLike |
Decimal
.toFixed(roundingMode, num) ⇒ Equivalent to new Decimal(num).toFixed(roundingMode)
See Decimal.js docs for ROUNDING_MODE constants
Kind: static function
Param | Type |
---|---|
roundingMode | num |
num | DecimalLike |
Number
.toNumber(a) ⇒ Equivalent to new Decimal(a).toNumber()
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
Decimal
.modulo(modulus, value) ⇒ Equivalent to new Decimal(value).modulo(modulus)
Kind: static function
Param | Type |
---|---|
modulus | DecimalLike |
value | DecimalLike |
Decimal
.toPower(power, value) ⇒ Equivalent to new Decimal(value).toPower(modulus)
Kind: static function
Param | Type |
---|---|
power | DecimalLike |
value | DecimalLike |
boolean
.isPositive(a) ⇒ Equivalent to new Decimal(a).isPositive()
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
boolean
.isNegative(a) ⇒ Equivalent to new Decimal(a).isNegative()
Kind: static function
Param | Type |
---|---|
a | DecimalLike |
Decimal
.dec(a) ⇒ Decrements a Decimal or value that may be converted into Decimal
Kind: static function
Returns: Decimal
- a minus 1
Param | Type |
---|---|
a | DecimalLike |
Decimal
.inc(a) ⇒ Increments a Decimal or value that may be converted into Decimal
Kind: static function
Returns: Decimal
- a plus 1
Param | Type |
---|---|
a | DecimalLike |
Decimal
.sum(a) ⇒ Returns the sum of an array of Decimals or values that may be converted into Decimal
Kind: static function
Returns: Decimal
- The sum of the values in a
Param | Type |
---|---|
a | Array.<DecimalLike> |
Decimal
.product(a) ⇒ Returns the product of an array of Decimals or values that may be converted into Decimal
Kind: static function
Returns: Decimal
- The product of the values in a
Param | Type |
---|---|
a | Array.<DecimalLike> |
Decimal
.max(a, b) ⇒ Returns the highest of a or b
Kind: static function
Returns: Decimal
- The highest of a or b
Param | Type |
---|---|
a | Array.<DecimalLike> |
b | Array.<DecimalLike> |
Decimal
.min(a, b) ⇒ Returns the lowest of a or b
Kind: static function
Returns: Decimal
- The lowest of a or b
Param | Type |
---|---|
a | Array.<DecimalLike> |
b | Array.<DecimalLike> |
Created by Wealth Wizards Software Engineering - http://wealthwizards.com