Removes all the specified keys from a JSON file and prints the cleaned result back

keepKeys.js

const fs = require("fs");
const path = require("path");

/**
 * Function to keep only specified keys in an object.
 * @param {Object} obj - The object to filter.
 * @param {Array<string>} keysToKeep - The keys to keep in the object.
 * @returns {Object} - A new object with only the specified keys.
 */
function keepObjectKeys(obj, keysToKeep) {
    const keptObj = {};
    keysToKeep.forEach((key) => {
        if (obj.hasOwnProperty(key)) {
            keptObj[key] = obj[key]; // Keep the key if it exists
        }
    });
    return keptObj;
}

/**
 * Main function to read, filter, and output JSON.
 * @param {string} filePath - The path to the JSON file.
 * @param {Array<string>} keysToKeep - The keys to keep in each object.
 */
function keepKeys(filePath, keysToKeep) {
    // Read the JSON file
    fs.readFile(filePath, "utf8", (err, data) => {
        if (err) {
            console.error(`Error reading file: ${err.message}`);
            process.exit(1);
        }

        try {
            const jsonData = JSON.parse(data); // Parse the JSON data

            // Check if jsonData is an array or an object
            const filteredData = Array.isArray(jsonData)
                ? jsonData.map((item) => keepObjectKeys(item, keysToKeep))
                : keepObjectKeys(jsonData, keysToKeep);

            console.log(JSON.stringify(filteredData, null, 2)); // Output filtered JSON
        } catch (parseError) {
            console.error(`Error parsing JSON: ${parseError.message}`);
            process.exit(1);
        }
    });
}

// Get command line arguments
const args = process.argv.slice(2);
if (args.length < 2) {
    console.error("Usage: keepKeys <filename.json> <key1> [<key2> ...]");
    process.exit(1);
}

const fileName = args[0];
const keysToKeep = args.slice(1);

// Resolve the full path of the file
const filePath = path.resolve(__dirname, fileName);

// Call the main function to keep specified keys
keepKeys(filePath, keysToKeep);