What are the differences between Object.assign() and the spread operator in JavaScript?
Gable E

In JavaScript, bothObject.assign() and the spread operator (...) can be used to perform object copying and merging operations. However, there are some important differences between the two. Here's a detailed explanation of the differences: 1. Syntax: -Object.assign(): -Object.assign() is a method that takes a target object as the first argument, followed by one or more source objects. - Spread Operator (...): - The spread operator is an operator that can be used with arrays, objects, and iterables. In the case of objects, it is used by prefixing an object with... within a new object or array literal. 2. Shallow vs. Deep Copy: -Object.assign(): -Object.assign() performs a shallow copy of objects. It copies the properties and values from the source objects into the target object. If a property value is an object or array, the reference to the original object is copied rather than creating a new object. - Spread Operator (...): - The spread operator can also be used to perform a shallow copy of an object. It creates a new object with the copied properties and values. However, if the property values are objects or arrays, the spread operator creates a new reference, resulting in a new object or array being created. 3. Merging Objects: -Object.assign(): -Object.assign() can be used to merge multiple objects into a single object. It overwrites the properties in the target object with the properties from the source objects. If multiple source objects have the same property, the rightmost source object's value takes precedence. - Spread Operator (...): - The spread operator can also be used to merge objects. By spreading multiple objects within a new object literal, you can combine their properties into a single object. If multiple objects have the same property, the rightmost object's value takes precedence. 4. Array Spread vs. Object Spread: -Object.assign(): -Object.assign() can only merge objects. It cannot be used to merge arrays. - Spread Operator (...): - The spread operator can be used to spread both objects and arrays. When used with arrays, it spreads the elements of the array into a new array. 5. Immutability: -Object.assign(): -Object.assign() mutates the target object. It modifies the properties of the target object, adding or updating them based on the source objects. - Spread Operator (...): - The spread operator creates a new object or array, ensuring immutability. It does not modify the original object or array but rather creates a new one with the copied properties or elements. Here's an example that demonstrates the differences betweenObject.assign() and the spread operator:

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const target = { a: 1, b: 2 };
const source = { b: 3, c: 4 };

// Using Object.assign()
const mergedObject = Object.assign({}, target, source);

// Using spread operator
const mergedObject2 = { ...target, ...source };

console.log(mergedObject);    // Output: { a: 1, b: 3, c: 4 }
console.log(mergedObject2);   // Output: { a: 1, b: 3, c: 4 }
console.log(target);          // Output: { a: 1, b: 2 }

In this example,Object.assign() and the spread operator are used to merge thetarget andsource objects into a new objectmergedObject andmergedObject2. Both methods create a new object with the combined properties oftarget andsource. However, note thatObject.assign() modifies the target object, while the spread operator does not. Consider the differences mentioned above and choose the method that best suits your requirements based on the desired outcome and behavior for your specific use case.

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