Expression has changed after it was checked during iteration by map keys in angular 2

Don’t bind to a method ...keys() in the template.
It will be called every time change detection runs.
object.keys() returns a new object every time it is called and Angular recognizes this as an unexpected change, which leads to your error.

You can fix it like

someMethod() {
  this.bindedAuthorsKeys = this.bindedAuthors.keys();
}

*ngFor="let author of bindedAuthorsKeys"