How to set object property (of object property of..) given its string name in JavaScript?

Question

Suppose we are only given

var obj = {};
var propName = \"foo.bar.foobar\";

How can we set the prop

Answer 1

Same as Rbar's answers, very useful when you're working with redux reducers. I use lodash clone instead of spread operator to support arrays too:

export function cloneAndPatch(obj, path, newValue, separator='.') {
    let stack = Array.isArray(path) ? path : path.split(separator);
    let newObj = _.clone(obj);

    obj = newObj;

    while (stack.length > 1) {
        let property = stack.shift();
        let sub = _.clone(obj[property]);

        obj[property] = sub;
        obj = sub;
    }

    obj[stack.shift()] = newValue;

    return newObj;
}