One-time data binding:
As its name suggests, the binding happens only once, ie, in the first digest cycle. One-time binding allows for a model or view to be updated ONCE from the value set by the controller upon the first digest
The syntax is {{::expression}}.
in angularjs and in angular 2 is here :angular 2 one time binding
Read-only
Sets the readonly attribute on the element, if the expression inside ngReadonly is truthy. Note that readonly applies only to input elements with specific types
The syntax is ng-readonly="expression"
and angular 2 have [readonly]="true"
Difference and Question
I guess both are similarly doing the same process but the only difference is read-only
is allow to disable the control. So what about the performance between those and their have any other difference?