Recursive Property Value Shortener for Deeply Nested JavaScript Objects

shorterValues.js

/**
 * Recursively shortens string values for specific properties in deeply nested objects/arrays.
 *
 * @param {any} obj - The input object or array to process.
 * @param {string[]} propsToShorten - Array of property names to shorten.
 * @param {number} maxLength - Max length for the shortened string.
 * @returns {any} - A new object/array with specified properties shortened.
 */
function shortenProps(obj, propsToShorten = ["b64Image", "base64Image"], maxLength = 30) {
  if (obj && typeof obj === 'object') {
    if (Array.isArray(obj)) {
      // Recursively handle array elements
      return obj.map(item => shortenProps(item, propsToShorten, maxLength));
    }

    const newObj = {};
    for (const key in obj) {
      if (!Object.prototype.hasOwnProperty.call(obj, key)) continue;

      if (propsToShorten.includes(key) && typeof obj[key] === 'string') {
        newObj[key] = obj[key].substring(0, maxLength) + '...';
      } else {
        newObj[key] = shortenProps(obj[key], propsToShorten, maxLength);
      }
    }
    return newObj;
  }

  return obj;
}

// Example usage:
const data = {
  b64Image: 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAA...veryLongStringHere',
  nested: {
    base64Image: 'data:image/jpeg;base64,anotherVeryLongStringHere...',
    arr: [
      { b64Image: 'anotherLongBase64Image...' },
      { something: 'else' }
    ]
  }
};

const result = shortenProps(data, ["b64Image", "base64Image"], 50);
console.log(result);