Node.js Interpreter

This Node.js project provides a flexible interpreter for evaluating JavaScript strings. It supports dynamic function parsing and can load external libraries based on user-specified configurations. The project is particularly useful for executing JavaScript code snippets with customized logic.

Features

• Library Loader: Loads required libraries dynamically to extend the functionality.
• Payload Support: Allows passing external arguments (payload) for evaluation within the JavaScript string.
• Run pure Javascript: In interpreter, you can run pure js code and logical operator here.

Installation

npm i formula-interpreter

Usage

The project exposes two primary functions:

interpretor(evalString, libraries, payload)

This function evaluates a given JavaScript string by optionally loading and utilizing libraries. The payload object is used to pass arguments into the evaluated string.

• evalString: A string containing the JavaScript code to evaluate.
• libraries: An array of library names to load from the libraries directory.
• EXTERNAL_VAR: An object containing values to pass into the evaluated code.

Example:

const evalString = "return 1+1";
const result = interpretor(evalString);
console.log(result); //output: 2

Usage of external variable.

const evalString = "return EXTERNAL_VAR.name.length"; // You can use external variables by EXTERNAL_VAR keyword.
const result = interpretor(evalString,[],{name:"Krishna"});
console.log(result); //output: 7

showLibAndProperties(library, propertyName, allAtOnce)

This function retrieves the available libraries and their properties.

• library: The name of the library to load.
• propertyName: The specific property or function within the library to retrieve.
• allAtOnce: A boolean flag to load all libraries and their properties at once.

Example:

For specific response.

const libraryInfo = showLibAndProperties('myLibrary', 'myFunction', false);

For all libraries, functions and their properties at once.

const libraryInfo = showLibAndProperties(null, null, true);

LIBRARIES

This module provides libraries so you don't need to know JavaScript code, you can use them easily. Below are the libraries available in the package.

LOGICAL

IF(condition, trueValue, falseValue)

Evaluates the given condition and returns either trueValue if the condition is true, or falseValue if the condition is false.

Parameters:

• condition: A boolean condition to evaluate.
• trueValue: The value to return if the condition is true.
• falseValue: The value to return if the condition is false.

Example

const evalString = "return IF(1 < 2, 'Yes', 'No')";
const result = interpretor(evalString, ['LOGICAL'], {});
console.log(result); // Output: Yes

AND(...args)

Evaluates multiple boolean expressions and returns true if all conditions are true.

Parameters:

• ...args: A variable number of boolean expressions.

Example

const andEvalString = "return AND(1 === 1, 2 === 2)";
const andResult = interpretor(andEvalString, ['LOGICAL'], {});
console.log(andResult); // Output: true

OR(...args)

Evaluates multiple boolean expressions and returns true if any condition is true.

Parameters:

• ...args: A variable number of boolean expressions.

Example:

const orEvalString = "return OR(1 === 2, 2 === 2)";
const orResult = interpretor(orEvalString, ['LOGICAL'], {});
console.log(orResult); // Output: true

STRING

This module provides libraries that allow you to manipulate strings without needing to know JavaScript code; you can use them easily. Below are the libraries available in the package.

Functions

CONCATSTR(...args)

Concatenates multiple strings into a single string.

Parameters:

• ...args: A variable number of strings to concatenate.

Example:

const evalString = "return CONCATSTR('Hello, ', 'world!', ' How are you?');";
const result = interpretor(evalString, ['STRING']);
console.log(result); // Output: Hello, World! How are you? 

STRLENGTH(str)

Returns the length of the given string.

Parameters:

• str: The string whose length is to be calculated.

Example:

const evalString = "return STRLENGTH('Hello, world!');";
const result = interpretor(evalString, ['STRING']);
console.log(result); // Output: 13