Get last defined element in path of lodash.get(object, path)

Question

Given an object:

const obj = {
  a: {
    b: {
      c: {
        d: 5
      }
    }
  }
};

I want a function similar to lodash.get(obj, path), which returns the last defined variable in the path:

console.log(_.something(obj, 'a.b.c.d')) // 5, which is obj.a.b.c.d
// because obj.a.b.c.d is defined

console.log(_.something(obj, 'a.b.c.e')) // { d: 5 }, which is obj.a.b.c
// because the path is only defined up to obj.a.b.c

console.log(_.something(obj, 'a.b.f')) // { c: { d: 5 } }, which is a.b
// because the path is only defined up to a.b

I can write it myself, but I wonder if I can do it with an existing lodash function. I've looked through the documentation, but nothing caught my eye.

Here's a rough implementation of what i want:

const safeGet = (object, path) => {
  const keys = path.split('.');
  let current = object;

  for (var i = 0; i < keys.length; i++){
    const val = current[keys[i]]
    if (val === undefined){
      return current;
    }
    current = val;
  }
}

Answer 1

There isn't a way to do that in Lodash by default, but here is a simpler function that I wrote than the one you currently have displayed. Hopefully this helps!

const obj1 = {
  a: {
    b: {
      c: {
        d: 5
      }
    }
  }
};

const obj2 = {
  a: {
    b: {
      c: {}
    }
  }
};

function getLastDefined(obj, searchPath) {
  return _.get(obj, searchPath) || getLastDefined(obj, _.chain(searchPath).split('.').reverse().tail().reverse().join('.').value());
}

console.log(getLastDefined(obj1, 'a.b.c.d'));
console.log(getLastDefined(obj2, 'a.b.c.d'));

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