A library for calculating mathematical expressions from a string
npm install string2mathimport string2math from 'string2math'let program_1 = string2math('(1.2 + 42) * -4.4e-2')
console.log(program_1.calculate()) // -1.9008let program_2 = string2math('var_1 + var_2 * 3')
console.log(program_2.calculate({ var_1: 1, var_2: 2 })) // 7
// complex variable names should be written in square brackets
program_2 = string2math('[EUR / USD] / [GBP / USD]')
console.log(program_2.calculate({ '[EUR / USD]': 1.04, '[GBP / USD]': 1.26 }))let program_3 = string2math('func(1, 2) + x')
console.log(program_3.calculate({ func: Math.max, x: 5 })) // 7
// or
program_3 = string2math('max(1, 2) + x')
console.log(program_3.calculate(Math, { x: 5 })) // 7let program_1 = string2math('x !== -Infinity ? x : NaN')
console.log(program_1.calculate({ x: 42 })) // 42let program_4 = string2math('vec2(1, 2) + vec2(3, 4) - -vec2(1, 1)')
console.log(
program_4.calculate({
vec2: (x, y) => ({ x: x, y: y }),
'+': (v1 = { x: 0, y: 0 }, v2) => ({ x: v1.x + v2.x, y: v1.y + v2.y }),
'-': (v1 = { x: 0, y: 0 }, v2) => ({ x: v1.x - v2.x, y: v1.y - v2.y }),
})
) // { x: 5, y: 7 }
/*
NOTE
The operators "+" and "-" can be placed before a variable, like "!" and "~":
-~2 - -3 * +!5
In this case, the function will be called like this:
addition(undefined, value) // +
subtraction(undefined, value) // -
!!! We need to keep this in mind !!!
*/All operators can be replaced:
'!' : 'Logical NOT',
'~' : 'Bitwise NOT',
'**' : 'Exponentiation',
'*' : 'Multiplication',
'/' : 'Division',
'%' : 'Remainder',
'+' : 'Addition',
'-' : 'Subtraction',
'<<' : 'Bitwise left shift',
'>>' : 'Bitwise right shift',
'>>>': 'Bitwise unsigned right shift',
'<' : 'Less than',
'<=' : 'Less than or equal',
'>' : 'Greater than',
'>=' : 'Greater than or equal',
'==' : 'Equality',
'!=' : 'Inequality',
'=' : 'Strict equality',
'===': 'Strict equality',
'!==': 'Strict inequality',
'&' : 'Bitwise AND',
'^' : 'Bitwise XOR',
'|' : 'Bitwise OR',
'&&' : 'Logical AND',
'||' : 'Logical OR',
'??' : 'Coalescing NaN'
By default, '=' is equivalent to '===', but they can be replaced independently.
// Nodes
import {
ProgramNode,
ConditionNode,
VariableNode,
ConstantNode,
FunctionNode,
OperatorNode,
} from 'string2math'
import string2math from 'string2math'
const program = string2math('(x + 1) * 2 - 3 >= func(4, 5) ? 6 : 7')
console.log(program)
// ||
// ||
// \ /
// \/
_ = /* ProgramN
777F
ode */ {
type: 'Program',
nodeChild: /* ConditionNode */ {
type: 'Condition',
nodeIf: /* OperatorNode */ {
type: 'Operator',
operator: '>=',
nodeLeft: /* OperatorNode */ {
type: 'Operator',
operator: '-',
nodeLeft: /* OperatorNode */ {
type: 'Operator',
operator: '*',
nodeLeft: /* OperatorNode */ {
type: 'Operator',
operator: '+',
nodeLeft: /* VariableNode */ {
type: 'Variable',
variable: 'x',
},
nodeRight: /* ConstantNode */ {
type: 'Constant',
constant: 1,
},
},
nodeRight: /* ConstantNode */ {
type: 'Constant',
constant: 2,
},
},
nodeRight: /* ConstantNode */ {
type: 'Constant',
constant: 3,
},
},
nodeRight: /* FunctionNode */ {
type: 'Function',
function: 'func',
nodeListOfArgs: [
/* ConstantNode */ {
type: 'Constant',
constant: 4,
},
/* ConstantNode */ {
type: 'Constant',
constant: 5,
},
],
},
},
nodeThen: /* ConstantNode */ {
type: 'Constant',
constant: 6,
},
nodeElse: /* ConstantNode */ {
type: 'Constant',
constant: 7,
},
},
}import string2math from 'string2math'
const program = string2math('1 + 2 % x * 3 ** y - 4 / 5')
console.log(program.toString())
// ((1 + ((2 % x) * (3 ** y))) - (4 / 5))
console.log(program.toArray())
/*
[
'(', '(', 1, '+', '(', '(', 2, '%', 'x', ')', '*', '(',
3, '**', 'y', ')', ')', ')', '-', '(', 4, '/', 5, ')', ')'
]
*/