happycalculator

calculator for natural formula like "1+2+3" for result 6,support custom function like sqrt(20) also whatever you want,support formulas loop, like sqrt(sqrt(20+20))

Changelog

2018-09-05

add supprot pow(^) for function convert and shunt.

中文

Install

$ npm install --save happycalculator

or bower

$ bower install --save happycalculator and it will apply happycalculator global to you

Usage

base

var happycalculator = require('happycalculator');
var formula = '20 * ( 10 + 20 ) / 20';
happycalculator.convert(formula);
//output: ['20', '*', '(', '10', '+', '20', ')', '/', '20']
happycalculator.shunt(formula);
//output: [ '20', '10', '20', '+', '*', '20', '/' ]
happycalculator.calculate(formula);
//output: 30

advance

//sqrt__custom is default seted to '$1*$2'
 
happycalculator.calculate('sqrt__custom(10)*20/20');
//output 100
 
happycalculator.addFormulas({'sqrt__custom' : '$1 + $1'}); //
happycalculator.calculate('sqrt__custom(10)*20/20');
//output 20
happycalculator.calculate(sqrt__custom('sqrt__custom(10))*20/20');
//output 40
happycalculator.removeFormulas(); //remove formulas added,and reset the formulas default
happycalculator.calculate('sqrt__custom(10)*20/20');
//output 100
 
happycalculator.addFormulas({'custom' : '$1 + $2 +$3'});
happycalculator.calculate('custom(10, 20, 30)')
//output 60
 
//support formulas loop
happycalculator.calculate('sqrt__custom(sqrt__custom(10))');
//output 10000
happycalculator.calculate('sqrt__custom(sqrt__custom(2+2))');
//output 256
 
 
//support sin,cos,tan,sqrt which was Math functions
happycalculator.calculate('sin(30)');
//output 0.5

support simple code

var code = `sum = $1 + $2;
a = 2;
b = 3;
sum(a,b)+a;
a = 3;
a+b;`
calculator.parse(code);
//output ['(2+3)+2', '3+3']
calculator.calculateCode(code);
//output [7, 6]

and that's all simple code support right now

API

convert(string_infix)

return an array that split with "+-*/",and if the string with values(example:a,ab,cos(20)) also that will be ok

shunt(string_infix)

return an array postinfx that with the Shunting-yard Algorithm converted,the core code was written from rosettacode and i change some code for the project

calculate(string_infix)

return the num calculated

addFormulas(formulas)

add custom formulas to the calculator,and the formula rule is looks like that{'key' => '$1+$2+$3'},key(1,2,3),default formula function has sqrt:'$1*$1' right now,its working on

removeFormulas()

remove all custom formulas you add in and defaults to the default project supported formulas