getPropsChainVal() - returns either the desired value or undefined

getPropsChainVal.js

/**
* getPropsChainVal function is helpful when we want to
* retrive value from a deep object and properties from
* anywhere in the middle can go missing resulting an error.
* `TypeError: Cannot read property '...' of undefined`
* The function returns either the desired value or undefined
*
* @param {Object} obj
* @param {String} propsChain  // 'data.sample.posts.items'
* @return value || undefined
*/
function getPropsChainVal(obj, propsChain) {
  if (typeof obj !== 'object' || typeof propsChain !== 'string') {
    throw new Error('Both args are required as an object and a string respectively');
  }
  propsChain = propsChain.split('.');
  
  return propsChain.reduce((obj, key) => {
    return typeof obj !== 'object'
      ? undefined 
      : obj[key];
  }, obj);
}

/**
* Example
*/
const obj = {
  data: {
    sample: {
      posts: {
        items: [1, 2, 3]
      }
    }
  }
};

const items = getPropsChainVal(obj, 'data.sample.posts.items');

console.log(items);

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