Map will create a new array from the old one (without reference to old one) and inside the map you create a new object and iterate over properties (keys) and ... ... <看更多>
To copy an object in JavaScript, you have three options: Use the spread ( ... ) syntax; Use the Object.assign() method; Use the JSON.stringify ... ... <看更多>
To mutate the data, make a shallow copy of the objects you want to mutate. So, the object returned directly or in an array will be in immutable/ ... ... <看更多>
