Run results for: JSON Stringification vs. cloneDeep vs. Custom Copy

Test name	Executions per second
Stringification Deep Copy	185672.6 Ops/sec
_.cloneDeep	85079.1 Ops/sec
Custom Copy	142588.9 Ops/sec

Stringification Deep Copy

let stringyCopy = JSON.parse(JSON.stringify({
    "name": {
        "first": "Billy",
        "last": "Bob",
        "middle": "Taylor"
    },
    "vehicles": [{
        "id": "1",
        "brand": "Toyota",
        "make": "Camry",
        "year": 2020,
        "nested": [1,2,3,4,5],
        "other": ["abc", 123],
        "and so forth": {
            "id": "1",
            "brand": "Toyota",
            "make": "Camry",
            "year": 2020,
            "nested": [1,2,3,4,5],
            "other": ["abc", 123],
            "test": {
                "first": "Billy",
                "last": "Bob",
                "middle": "Taylor"
            }
        }
    }, {
        "id": "1",
        "brand": "Toyota",
        "make": "Camry",
        "year": 2020,
        "nested": [1,2,3,4,5],
        "other": ["abc", 123],
        "junk": {
            "id": "1",
            "brand": "Toyota",
            "make": "Camry",
            "year": 2020,
            "nested": [1,2,3,4,5],
            "other": ["abc", 123],
            "so on": {
                "id": "1",
                "brand": "Toyota",
                "make": "Camry",
                "year": 2020,
                "nested": [1,2,3,4,5],
                "other": ["abc", 123]
            }
        }
    }]
}));

_.cloneDeep

let deepCopy = _.cloneDeep({
    "name": {
        "first": "Billy",
        "last": "Bob",
        "middle": "Taylor"
    },
    "vehicles": [{
        "id": "1",
        "brand": "Toyota",
        "make": "Camry",
        "year": 2020,
        "nested": [1,2,3,4,5],
        "other": ["abc", 123],
        "and so forth": {
            "id": "1",
            "brand": "Toyota",
            "make": "Camry",
            "year": 2020,
            "nested": [1,2,3,4,5],
            "other": ["abc", 123],
            "test": {
                "first": "Billy",
                "last": "Bob",
                "middle": "Taylor"
            }
        }
    }, {
        "id": "1",
        "brand": "Toyota",
        "make": "Camry",
        "year": 2020,
        "nested": [1,2,3,4,5],
        "other": ["abc", 123],
        "junk": {
            "id": "1",
            "brand": "Toyota",
            "make": "Camry",
            "year": 2020,
            "nested": [1,2,3,4,5],
            "other": ["abc", 123],
            "so on": {
                "id": "1",
                "brand": "Toyota",
                "make": "Camry",
                "year": 2020,
                "nested": [1,2,3,4,5],
                "other": ["abc", 123]
            }
        }
    }]
});

Custom Copy

function copy(value) {
  if (value === null || value === undefined) {
    return value;
  }
  
  // Array, just call copy on each entry, map returns a new array.
  if (Array.isArray(value)) {
    return value.map(copy);
  } 
  // Create a new object and copy everything
  else if (typeof value === 'object') {
    return Object.keys(value).reduce((copied, key) => {
      copied[key] = copy(value[key]);
      return copied;
    }, {});
  } else {
    // Otherwise it is a scalar anyways.
    return value;
  }
}
const customCopy = copy({
    "name": {
        "first": "Billy",
        "last": "Bob",
        "middle": "Taylor"
    },
    "vehicles": [{
        "id": "1",
        "brand": "Toyota",
        "make": "Camry",
        "year": 2020,
        "nested": [1,2,3,4,5],
        "other": ["abc", 123],
        "and so forth": {
            "id": "1",
            "brand": "Toyota",
            "make": "Camry",
            "year": 2020,
            "nested": [1,2,3,4,5],
            "other": ["abc", 123],
            "test": {
                "first": "Billy",
                "last": "Bob",
                "middle": "Taylor"
            }
        }
    }, {
        "id": "1",
        "brand": "Toyota",
        "make": "Camry",
        "year": 2020,
        "nested": [1,2,3,4,5],
        "other": ["abc", 123],
        "junk": {
            "id": "1",
            "brand": "Toyota",
            "make": "Camry",
            "year": 2020,
            "nested": [1,2,3,4,5],
            "other": ["abc", 123],
            "so on": {
                "id": "1",
                "brand": "Toyota",
                "make": "Camry",
                "year": 2020,
                "nested": [1,2,3,4,5],
                "other": ["abc", 123]
            }
        }
    }]
});