@nexssp/expression-parser

Lightweight JavaScript expression parser with error diagnostics and object interpolation.

Features

• Safe evaluation of embedded JavaScript expressions
• Intelligent variable name suggestions for undefined variables
• Recursive object parsing
• Clear error reporting with ANSI formatting

Installation

npm install @nexssp/expression-parser

Usage

Basic Expression Parsing

const { expressionParser } = require("@nexssp/expression-parser");

const data = { a: 5, b: 10 };
console.log(expressionParser("Sum: ${a + b}", data));
// Output: "Sum: 15"

Object Data Parsing

const { parseData } = require("@nexssp/expression-parser");

const template = {
  greeting: "Hello ${name}!",
  calculation: "${x * y}",
  nested: {
    value: "${Math.PI.toFixed(2)}"
  },
  omitted: "Will not parse: ${undefined}"
};

const result = parseData(template, ["omitted"]);
console.log(result);
/* Output:
{
  greeting: "Hello John!",
  calculation: 50,
  nested: { value: "3.14" },
  omitted: "Will not parse: ${undefined}"
}
*/

Error Handling

API

expressionParser(exp, data)

Evaluates expressions in strings while handling errors gracefully.

parseData(object, omittedKeys)

Recursively processes object values, skipping specified keys.

Security

Important: Uses JavaScript evaluation - only use with trusted input sources.