Circular Structure to JSON, UI Runtime Error TypeError

Question

I am getting an error when trying to parse and stringify some JSON data.

On this line:

this.copyOfColumns = JSON.parse(JSON.stringify(Object.assign([], this.columns)));

Here is the entire @Input (using Angular 4):

  @Input()
  set gridColumns(gridColumnsArr: Array<object>) {
    console.log('gridColumnsArr');
    console.log(gridColumnsArr);
    this.columns = this.sortActiveAndInactiveColumns(gridColumnsArr);
    console.log('this.columns');
    console.log(this.columns);
    this.copyOfColumns = JSON.parse(JSON.stringify(Object.assign([], this.columns)));
    console.log('this.copyOfColumns');
    console.log(this.copyOfColumns);
  }

Here is the data logged to the console (this.columns)...and the error(s) following:

why did you not set this.copyOfColumns = JSON.stringify(Object.assign([], this.columns)); — Hien Nguyen
– Hien Nguyen, Commented Apr 15, 2019 at 14:01

Florian Richter · Accepted Answer · 2019-04-15 14:57:07Z

1

I assume you want to deep copy the array by using JSON.parse(JSON.stringify()). Apparently your data structure has circular references which fails the JSON.stringify().

Either you should sanitize your data to not contain ciruclar references or you could try using a library like flatted

answered Apr 15, 2019 at 14:57

Florian Richter

1018 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Circular Structure to JSON, UI Runtime Error TypeError

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related