precise-calculator

Precise Calculator

Usage

Install globally to use repl

npm install -g precise-calculator

$ pcalc
$C> 1 + 1
2

Or install in project to use api

const $C = require('precise-calculator')
// (1 + 1) * 1 / 1 - 1
$C(1).add(1).mul(1).div(1).sub(1).v()

API

Calculator

const $C = require('precise-calculator')
$C(1)
$C('1')
new $C.Calculator(1)
new $C.Calculator('1')

add(n)/$add(c)

Arithmetic operator +.

$C(1).add(1)
$C(1).add('1')
$C('1').$add($C(1))

sub(n)/$sub(c)

Arithmetic operator -.

$C(1).sub(1)
$C(1).sub('1')
$C('1').$sub($C(1))

mul(n)/$mul(c)

Arithmetic operator *.

$C(1).mul(1)
$C(1).mul('1')
$C('1').$mul($C(1))

div(n)/$div(c)

Arithmetic operator /.

$C(1).div(1)
$C(1).div('1')
$C('1').$div($C(1))

round(precision)/rv(precision)

Use default rounding method to round and return the value with special precision. Default rounding method is round-half-up, which can be changed by setup()

$C(3.141).round(2) // 3.14
$C(3.145).rv(2) // 3.15

upRound(precision)/uv(precision)

Use round-half-up to round and return the value with special precision.

$C(3.141).upRound(2) // 3.14
$C(3.145).uv(2) // 3.15

evenRound(precision)/ev(precision)

Use round-half-even to round and return the value with special precision.

$C(3.145).evenRound(2) // 3.14
$C(3.155).ev(2) // 3.16

ceil(precision)/cv(precision)

Ceil and return the value with special precision.

$C(3.141).ceil(2) // 3.15
$C(3.155).cv(2) // 3.16

floor(precision)/fv(precision)

Floor and return the value with special precision.

$C(3.146).floor(2) // 3.14
$C(3.151).fv(2) // 3.15

r(precision)/ru(precision)/re(precision)/rc(precision)/rf(precision)

Use rounding method to round and return itself, usually in the middle of calculations

$C(1).div(8).r(2).mul(5).v() // 0.65
$C(1).div(8).ru(2).mul(5).v() // 0.65
$C(1).div(8).re(2).mul(5).v() // 0.6
$C(1).div(8).rc(2).mul(5).v() // 0.65
$C(1).div(8).rf(2).mul(5).v() // 0.6

• r use default rounding method
• ru use round-half-up rounding method
• re use round-half-even rounding method
• rc use ceil rounding method
• rf use floor rounding method

format(fmt='#,##0.00', prefix='', suffix='')/fmt(fmt='#,##0.00', prefix='', suffix='')

Format the value with special formatter. format only, no round, if you want round please round before format.

$C(1234.1).format('#,##0.00') // 1,234.10
$C(1234.1).format('#,##0.00', '$') // $1,234.10
$C(12.3).format('#,##0.00', '', '%') // 12.30%

thousands(precision=2)

Format use thousands sperator.

$C(1234.1).format('#,##0.00') // 1,234.10
$C(1234.1).format('#,##0.00', '$') // $1,234.10
$C(12.3).format('#,##0.00', '', '%') // 12.30%

currency(currency, positiveSign=false)

Format use thousands sperator and with prefix currency.

signed(prefix='', precision = 2)

Force sign even for positive numbers.

unsigned(prefix='', precision = 2)

Force unsign even for negative numbers.

v()/value()

Return the number value of current result.

$C(1).add(2).v() // number value `3`
$C(1).add(2).value() // number value `3`

vs()

Return the string value of current result.

$C(1).add(2).vs() // string value `3`

ve()

Return the scientific notation value of current result.

$C(10).mul(100).ve() // string value `1e+3`

compile(expr, ...args)/ccompile(expr, ...args)/cc(expr, ...args)/ocompile(expr)/oc(expr)

Compile the arithmetic expression to corresponding function. There must be spaces before and after the operator in the expression. ccompile()/cc() compiled and cached the compilation result for reuse. ocompile()/oc() compiled as a function with a object argument and cached the compilation result for reuse.

$C.compile('1 +1') // invalid expression
$C.compile('1+1') // invalid expression

const formula1 = $C.compile('1 + 1') // valid expression
const formula2 = $C.ccompile('(x + y) * z', 'x', 'y', 'z') // valid expression
const formula3 = $C.ocompile('(x + y) * z') // valid expression

// Execute formula
console.log(formula1()) // 2
console.log(formula2(1, 2, 3)) // 9
console.log(formula3({x: 1, y: 2, z: 3})) // 9

More settings can be set in curly braces after all parentheses. Such as, rounding, formatting, etc.

const d = {x:1.23, y:1.224, z:3}
$C.compile('((d.x + d.y) * d.z)', 'd')(d) // 7.362
$C.compile('((d.x + d.y) * d.z){.2R}', 'd')(d) // 7.36
$C.compile('((d.x + d.y){.2R} * d.z)', 'd')(d) // 7.35
$C.compile('((d.x + d.y){.2R} * d.z){.1R}', 'd')(d) // 7.4

Functions supportted in expression

Built-in functions

• max(x, y, ..., z) Returns max value of arguments
• min(x, y, ..., z) Returns min value of arguments
• pow(x, y) Returns the value of a base expression taken to a specified power
• abs(x) Returns the absolute value of a number

$C.compile('1 + pow(3, 2)') // 10
$C.compile('1 + max(3, 2)') // 4
$C.compile('1 + min(3, 2)') // 3

Extend functions, should define a pair of functions, name() and $name(). The arguments and return values of functions that start with $ are instances of Calculator

$C.square = (x)=>Math.pow(x,2)
$C.$square = ($x)=>$C(Math.pow($x,2))
1 + square(2) // 5
1 + square(1 + 1) // 5

Expression settings

Settings arguments{[prefix][format][mode][suffix]}

• prefix used in format() as prefix argument, supports $¥
• format used in format(), and rouding methods if there is any rounding mode. Supports two formats, standard format(#,##0,#,##0.00,.00) and digital mode(3, 3.2, .2)
• mode rounding mode:
  • R use default rounding method, (1.123){.2R} means $C(1.123).r(2).v()
  • U use round-half-up method, (1.123){.2U} means $C(1.123).ru(2).v()
  • E use round-half-even method, (1.123){.2E} means $C(1.123).re(2).v()
  • C use round-ceil method, (1.123){.2C} means $C(1.123).rc(2).v()
  • F use round-floor method, (1.123){.2F} means $C(1.123).rf(2).v()
  • S/s specify the result to return a string, and can be used with rounding mode, (1.123){S} means $C(1.123).vs(), (1.123){.2Rs} means $C(1.123).r(2).vs()
  • e specify the result to return a scientific, (1.123){e} means $C(1.123).ve()
  • P specify the result as a percentage with the suffix %, (1.123){.P} means $C(1.123).mul(100).format('.','','%')
• suffix used in format() as suffix argument, supports %

Special format

• Support front currency, for example

$C.ocompile('$(1.1 + 1.2)') // $2.3
$C.ocompile('¥(1.1 + 1.2)') // ¥2.3

• Support function alias, for example(...).round(2)

$C.ocompile('(1.1 + 1.2).round(2)') // $C(1.1).add(1.2).r(2).v()
$C.ocompile('(1.1 + 1.2).upRound(2)') // $C(1.1).add(1.2).ru(2).v()
$C.ocompile('(1.1 + 1.2).evenRound(2)') // $C(1.1).add(1.2).re(2).v()
$C.ocompile('(1.1 + 1.2).ceil(2)') // $C(1.1).add(1.2).rc(2).v()
$C.ocompile('(1.1 + 1.2).floor(2)') // $C(1.1).add(1.2).rf(2).v()

$compile(expr, ...args)/$ccompile(expr, ...args)/$cc(expr, ...args)/$ocompile(expr)/$oc(expr)

Compile the arithmetic expression to corresponding function, which the function's result is Calculator. Used to calculate intermediate results, so formatting cannot be used.

const fn = $C.$ocompile('((x + y) * z){.2R}') // $(x).add(y).mul(z).r(2)
const result = fn({x: 1, y: 2, z: 3}) // result is instanceof Calculator
result.format('#,##0.00') // 9.00
result.format('#,##0.0', '$') // $9.0

eval(expr, ...args)

Calculate the value of the expression. First half of the args is the name, and the second half is the value.

$C.eval('x + y', 'x', 'y', 1, 2) // 3
$C.eval('1 + 2') // 3
$C.eval('a.x + a.y', 'a', {x:1, y:2}) // 3

withStrict()/withoutStrict()

Use or not use strict mode. With strict mode, will check the input value whther is a number by isNaN