Spread Out Appoint Document For Free

Though they look the same, the context defines their behavior: Spread Operator expands an iterable into its individual elements. Rest Operator collects multiple elements and condenses them into a single array.

The spread operator is commonly used to make deep copies of JS objects. When we have nested arrays or nested data in an object, the spread operator makes a deep copy of top-level data and a shallow copy of the nested data. Using this operator makes the code concise and enhances its readability.

Comparing with Object.assign() Note that Object.assign() can be used to mutate an object, whereas spread syntax can't. In addition, Object.assign() triggers setters on the target object, whereas spread syntax does not.

Rest Parameter collects all remaining elements into an array. Spread Operator expands collected elements such as arrays into single elements. The spread syntax only does a shallow copy one level deep. Only the last parameter can be a rest parameter.

Object. assign . We aren't actually using the returned value of the function at all, but we are modifying our target object which we have referenced with the const food . Spread on the other hand is an operator which copies properties of one object into a new object.

The spread operator (?) with objects is used to create copies of existing objects with new or updated values or to make a copy of an object with more properties. Let's take an example of how to use the spread operator on an object, Example: javascript.

The spread operator works on a map the same way it does on an array. The main difference is that it returns a list of pairs instead of single values.