Logical Expressions

A library to evaluate logical expressions.

🛠 Install

npm or yarn

Install the @zk-kit/logical-expressions package with npm:

npm i @zk-kit/logical-expressions
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or yarn:

yarn add @zk-kit/logical-expressions
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CDN

You can also load it using a script tag using unpkg:

<script src="https://unpkg.com/@zk-kit/logical-expressions"></script>
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or JSDelivr:

<script src="https://cdn.jsdelivr.net/npm/@zk-kit/logical-expressions"></script>
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📜 Usage

Supported logical operators: and, or, not, xor.

All other existing logical operators (nand, nor, xnor) can be generated using the supported logical operators.

Tokenize a logical expression

# tokenize(): string[]

Tokenizes a logical (boolean) expression. Splits the expression into meaningful tokens.

import { tokenize } from "@zk-kit/logical-expressions"

const expression = "true and false or ( true and true )"

const tokens = tokenize(expression)

console.log(tokens)
// Output: ["true", "and", "false", "or", "(", "true", "and", "true", ")"]
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Precedence of a logical operator

# precedence(): number

Returns the precedence of a logical operator. If the operator is not supported, the precedence will be 0.

import { precedence } from "@zk-kit/logical-expressions"

const result = precedence("and")

console.log(result) // Output: 1
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Apply Operator

# applyOperator(): boolean

Applies unary or binary operators to boolean values.

import { applyOperator } from "@zk-kit/logical-expressions"

// Unary operator
const result1 = applyOperator("not", true)
console.log(result1) // Output: false

// Binary operator
const result2 = applyOperator("and", true, false)
console.log(result2) // Output: false
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Evaluate a tokenized logical expression

# evaluate(): boolean

Evaluates a tokenized logical (boolean) expression.

There is no need to verify the correctness of the logical expression before calling the evaluate function, as this will be checked during the evaluation. If the expression is incorrect, an error will be thrown automatically.

Example of correct logical expression: "true and false".

Example of incorrect logical expression: "true true and false".

import { evaluate } from "@zk-kit/logical-expressions"

const expression = ["true", "and", "false"]

const result = evaluate(expression)

console.log(result) // Output: false
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