angular 中的变量 scope 5

Question

I know it's silly question but would like to know exact scope of variable of this.

I have tried following and if i make any changes in data, response is getting changed too.

I have tried following:

private response;
private data;

getdata() {
  this.service.getdata().subscribe((res: any) => {

    if (res) {
      this.response = res;
      this.data = res;
    }
  });
}

If i use data as input parameter for other component and make any changes on that, my this.response is also getting changed.

I am not sure what to do to retain the previous data.

Answer 1

Its because both response and data are sharing the same object reference.

Your code within if condition is nothing but a shallow copy of each other

this.response = this.data = res; 

Hence when you change one value the other value also gets changed,

In order to avoid this from happening you can do the following

this.data = Object.assign({},res);

OR

this.data = {...res}

Read this for more details on shallow copy and deep copy