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Deprecation Guide for Function as test in Ember.deprecate, Ember.warn, Ember.assert

until: 2.5.0
id: function-as-test-in-ember-deprecate-ember-warn-ember-assert

Calling Ember.deprecate, Ember.warn or Ember.assert with a function as test argument is deprecated.

You can no longer pass arguments of type function to these methods. Following calls will trigger deprecations:

const message = 'Test message.';
const options = { id: 'test', until: '3.0.0' };

// passing function
Ember.deprecate(message, function() {
  return true;
}, options);

const myConstructor = {}.constructor;

// passing constructor (also a function)
Ember.warn(message, myConstructor, options);

// passing function with double arrow syntax
Ember.assert(message, () => true, options);



You have 3 options to refactor second argument from function to boolean:

  1. Use IIFE.
  2. Use !!Constructor for constructors.
  3. Pass boolean directly instead of wrapping it in function.


// ... message, options omitted for brevity

// passing IIFE (1)
Ember.deprecate(message, (function() {
    return true;
})(), options);

const myConstructor = {}.constructor;

// passing !!constructor (2)
Ember.warn(message, !!myConstructor, options);

// passing boolean directly (3)
Ember.assert(message, true, options);


In a future version functions will be treated as truthy values instead of being executed.