javascripttypescriptalgorithm

JavaScript - Flatten nested JSON object

How could I turn this

{
  "root": {
    "sub": 1,
    "sub2": 2,
  },
  "root2": 3
}

into this

{
  "root.sub": 1,
  "root.sub2": 2,
  "root2": 3
}

though a function programmatically?

I have literally no idea how I would do it, but I've tried to create a function which uses a cursor/pointer to jump through all child objects, but could not find a way to repeat the process.

Solution

  • This may be an alternative;

    function flattenObject(obj, prefix = '') {
    let flattenedObject = {};
    
    for (let key in obj) {
        if (typeof obj[key] === 'object' && obj[key] !== null) {
            const nestedFlattenedObject = flattenObject(obj[key], prefix + key + '.');
            flattenedObject = {...flattenedObject, ...nestedFlattenedObject};
        } else {
            flattenedObject[prefix + key] = obj[key];
        }
    }
    
    return flattenedObject;
}

const nestedObject = {
  "root": {
    "sub": 1,
    "sub2": 2,
  },
  "root2": 3
}

const flattenedObject = flattenObject(nestedObject);
console.log(flattenedObject);