What is deep merge in JavaScript and can you provide examples?

What is deep merge in JavaScript and can you provide examples?

Deep merge in JavaScript refers to merging two or more objects recursively, combining their properties.

Can you show me a code example of deep merging two objects?

Sure! Here's a simple example:

const obj1 = { a: 1, b: { c: 2 } };
const obj2 = { b: { d: 3 }, e: 4 };

const deepMerge = (target, source) => {
    for (const key in source) {
        if (source[key] instanceof Object) {
            if (!target[key]) Object.assign(target, { [key]: {} });
            deepMerge(target[key], source[key]);
        } else {
            Object.assign(target, { [key]: source[key] });
        }
    }
    return target;
};

const merged = deepMerge(obj1, obj2);
console.log(merged);
// Output: { a: 1, b: { c: 2, d: 3 }, e: 4 }

What libraries can I use for deep merging in JavaScript?

You can use libraries like Lodash (_.merge), Ramda, or deepmerge for deep merging objects.