is-function-pure

is-function-pure

is-function-pure is a JavaScript utility for detecting if function is pure.

Installation

To install the package, use npm:

npm install is-function-pure

Usage

isPure(singleFunctionSourseCode)

The isPure function checks if a single function in the given code is pure. It returns true if the function is pure, and false otherwise.

Input: A string containing a single JavaScript function.

Output: A boolean indicating whether the function is pure.

const { isPure } = require('is-function-pure');

const pureFunction = `
  function multiply(a, b) {
    return a * b;
  }
`;

console.log(isPure(pureFunction)); // Output: true

separate(sourceCode)

The separate function analyzes a block of code and returns an object containing two arrays: pure and impure. Each array holds details about the functions found in the code.

Input: A string containing JavaScript code.

Output: An object with pure and impure arrays.

const { separate } = require('is-function-pure');

const code = `
  const x = 5;
  function add(a, b) {
    return a + b;
  }
  function impure(a) {
    return a + x;
  }
`;

const result = separate(code);

console.log('Pure Functions:', result.pure);
console.log('Impure Functions:', result.impure);

Function is NOT pure if it:

• has references to outside scopes
• uses Date() or Math.random()
• uses this
• does not have return statement

More about what is considered pure or not you can read in test cases: https://github.com/senad87/is-function-pure/blob/main/tests/main-test.js https://github.com/senad87/is-function-pure/blob/main/tests/purity-detector-test.js

Testing

Tests are written using chai and can be run with:

npm run test

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