AbilityAssertion
Hierarchy
Assertion
↳ AbilityAssertion
Index
Constructors
Properties
Methods
Constructors
constructor
+ new AbilityAssertion(asserter: Asserter): AbilityAssertion
Inherited from Assertion.constructor
Overrides void
Parameters:
| Name | Type |
|---|---|
asserter | Asserter |
Returns: AbilityAssertion
Properties
api
• api: Map‹string, any› = new Map([
// Validation - ensures that Entity is able to handle an action(throws error)
[
'ensure.is.ableTo',
new Proxy(this, {
get(target: any, propKey: string): any {
const entity = target.asserter.getEntity();
if (typeof entity[propKey] === 'function') {
const proxifiedMethod = new Proxy(entity[propKey], {
apply(_targetMethod, _thisArg, args): any {
entitySAVE_STATE_METHOD_KEY;
const result = entitypropKey;
entityROLLBACK_STATE_METHOD_KEY;
target.asserter.clearAction();
return result;
},
});
return proxifiedMethod;
}
return entity[propKey];
},
}),
],
// Evaluation - evaluates that Entity is able to handle an action(returns boolean)
[
'is.ableTo',
new Proxy(this, {
get(target: any, propKey: string): any {
const entity = target.asserter.getEntity();
if (typeof entity[propKey] === 'function') {
const proxifiedMethod = new Proxy(entity[propKey], {
apply(_targetMethod, _thisArg, args): any {
entitySAVE_STATE_METHOD_KEY;
let isAble = true;
try {
entitypropKey;
} catch (e) {
isAble = false;
}
entityROLLBACK_STATE_METHOD_KEY;
return isAble;
},
});
return proxifiedMethod;
}
return entity[propKey];
},
}),
],
])
Since our goal is to enable expressive API in form of:
example
We need to use Proxy to pass-through all calls to the entity itself (entity state will be not changed upon invoking method).
remarks
The entity.ensure getter-method will return a Proxified instance of the
Entity. This proxified instance listens to all get methods and
catches the requested method name.
If the requested get method is named is - is an existing api registered
on Asserter with AbilityAssertion as assertion API.
This will return an object that will include property:
That will be fired with code below.
remarks
Same approach is used for evaluator api is.ableTo(returning boolean
by catching any thrown error) - however it was replaced by
Entity.prototype.can method directly build on Entity.
The is.ableTo legacy code is still available to show possibilities of
building custom assertion apis without direct modification of
Entity or its subclasses - to have a assertion api code shared
'globally'.
asserter
• asserter: Asserter
Inherited from Assertion.asserter
Overrides void
Methods
getApi
▸ getApi(): Map‹string, Function›
Inherited from Assertion.getApi
Overrides void
Returns: Map‹string, Function›