Function

readOnly (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:745

Available since v1.5.0 

import { readOnly } from '@ember/object/computed';
dependentKey
String
returns
ComputedProperty
computed property which creates a one way computed property to the original value for property.

Where oneWay computed macro provides oneWay bindings, the readOnly computed macro provides a readOnly one way binding. Very often when using the oneWay macro one does not also want changes to propagate back up, as they will replace the value.

This prevents the reverse flow, and also throws an exception when it occurs.

Example:

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import { set } from '@ember/object';
import { readOnly } from '@ember/object/computed';

class User {
  constructor(firstName, lastName) {
    set(this, 'firstName', firstName);
    set(this, 'lastName', lastName);
  }

  @readOnly('firstName') nickName;
});

let teddy = new User('Teddy', 'Zeenny');

teddy.nickName; // 'Teddy'

set(teddy, 'nickName', 'TeddyBear'); // throws Exception
// throw new EmberError('Cannot Set: nickName on: <User:ember27288>' );`

teddy.firstName; // 'Teddy'