@pestras/eq

Eq

Evaluates Math equations with variables

install

$ npm i @pestras/eq

Get Started

import { eq } from '@pestras/eq';

const eq = new Eq("2x^2(3 + cos(y))"); // auto parse to "2 * x ^ 3 * (3 + cos(y))"
const result = eq.evaluate({ x: 3, y: 30 });

console.log(result);  // 56.776526097976515 

Multi Equations

We can define multi equations and reference each other.

// Adding name to the second param.
// names must not preceeded by number
new Eq("2x^2(3 + cos(y))", "myEq"); // auto parse to "2 * x ^ 3 * (3 + cos(y))"

const eq = new Eq("log(x) / (myEq + 6)");
const result = eq.evaluate({ x 3, y: 30 });

console.log(result);  // 0.017500367684466715

We can fetch saved equation any where as follows:

const myEq = Eq.Get('myEq');

Errors

Eq may produce four types of errors:

• EqError: General error.
• EqRefError: When unknown variable or math function found.
• EqDivisionByZeroError: Thrown when division by zero was found.
• EqUnknownOperatorError: Unknown operator found.

try {
  new Eq("x + y").evaluate({ x: 1 });
} catch (e) {
  console.log(e.name) // EqRefError
  console.log(e.message) // 'y' is undefined
}

Supported Operators

• Add: +
• Subtract: -
• Multiply: *
• Division: /
• Remainder: %
• Power: ^
• Nth Root: colon : as "27 : 3" will produce 3

Supported Math Functions

Almost all javascript Math lib methods.

• exp
• expm1
• log
• log10
• log2
• ln
• sin
• sinh
• asin
• asinh
• cos
• cosh
• acos
• acosh
• tan
• tanh
• atan
• atan2
• atanh
• trunc
• floor
• ceil
• round
• sqrt
• cbrt
• abs
• sign

Supported Math Constants

All javascript Math lib constants.

• PI
• E
• LN10
• LN2
• LOG10E
• LOG2E
• SQRT1_2
• SQRT12

Thank you