Which is more efficient: Using TypeScript's Object.assign() or creating a new object?

Question

Which is more efficient: Using TypeScript's Object.assign() or creating a new object?

Seeking advice on two different approaches to implementing a method with a constant. Unsure about the better option. Can someone provide guidance? Thank you!

Approach 1: Declaring the constant outside of the class, causing it to be invoked only once but requiring the return of a new variable.

const X = {a: 0, b: 1, c: 2}
export class A{
   private method a (val: any) { 
       return {...X, ...val}
}}

Approach 2: Placing the constant within the method, resulting in the invocation of the constant every time the method is called (twice in this scenario) but eliminating the need for creating a new object.

export class A{
   private method a (val: any) { 
       const x = {a: 0, b: 1, c: 2}
       return Object.assign(x, val)
}}

typescript deep-copy

Answer 1

Answer №1

In my opinion, there is no one-size-fits-all solution to this issue. It's important to consider the scope of variables rather than just how often they are called or created. When declaring a constant outside the scope of a class, any other class or function within that scope can access and potentially modify it, leading to unexpected bugs in your code.

Let's imagine you have a variable x set to 5

function isEven(value: number) {
    // Here I'm changing the value of x
    x = 2

    return value % 2 === 0;
}

function destroyTheWorldIfEven(value: number) {
  if(isEven(value)){
      console.log("x is", x)
      console.log("your world has been destroyed")
      return
  }
  
  return console.log("you are safe")
}

// Initially x is 5
destroyTheWorldIfEven(x)

// In the next call x becomes 2 due to the reassignment in isEven function
destroyTheWorldIfEven(x)

If you don't need to share the constant variable among functions or classes, it's best to keep it within the scope of class A. Here are some suggestions:

If const x is only used in one method of class A, keep it within that method.
If const x is used by multiple methods from class A, make it a private attribute.
If const x belongs to class A but needs to be accessed by other classes, make it a public attribute but avoid defining a setter method for it.

Here are some helpful resources for further reading:

JavaScript scope

JavaScript hoisting

JavaScript closure

SOLID principles

The SOLID principles are particularly crucial when working with Object-Oriented Programming, so be sure to give them a thorough read.

Answer 2

In my opinion, there is no one-size-fits-all solution to this issue. It's important to consider the scope of variables rather than just how often they are called or created. When declaring a constant outside the scope of a class, any other class or function within that scope can access and potentially modify it, leading to unexpected bugs in your code.

Let's imagine you have a variable x set to 5

function isEven(value: number) {
    // Here I'm changing the value of x
    x = 2

    return value % 2 === 0;
}

function destroyTheWorldIfEven(value: number) {
  if(isEven(value)){
      console.log("x is", x)
      console.log("your world has been destroyed")
      return
  }
  
  return console.log("you are safe")
}

// Initially x is 5
destroyTheWorldIfEven(x)

// In the next call x becomes 2 due to the reassignment in isEven function
destroyTheWorldIfEven(x)

If you don't need to share the constant variable among functions or classes, it's best to keep it within the scope of class A. Here are some suggestions:

If const x is only used in one method of class A, keep it within that method.
If const x is used by multiple methods from class A, make it a private attribute.
If const x belongs to class A but needs to be accessed by other classes, make it a public attribute but avoid defining a setter method for it.

Here are some helpful resources for further reading:

JavaScript scope

JavaScript hoisting

JavaScript closure

SOLID principles

The SOLID principles are particularly crucial when working with Object-Oriented Programming, so be sure to give them a thorough read.

Which is more efficient: Using TypeScript's Object.assign() or creating a new object?

Answer №1

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