werehamster / avers-js Goto Github PK

When a variant property changes we need to return two operations, one to change the type and another one to change the content.

Instead of using a global Object.observe() callback, store it in the object that is being observed (under a private property). Then provide Avers.flushChanges(obj, recursive) to flush changes of a specific object.

I consider it a bug in the parser if it crashes when it can't decode a variant property. It should instead set the property to null. migrateObject can then take care of setting it to the default value if one is provided.

Now that we've moved aversProperties to a private property and no longer expose it to users of the library, we should consider the same with event functions (on, listenTo, trigger etc).

We can expose the event functions through the Avers module. However, they create an _events property which is used to store callbacks that are attached to the object. What I have in mind is to store them in a WeakMap instead. It would probably have a small performance impact. Will need to benchmark it.

We have all the information about the properties in this._modelProperties. Use that to parse the JSON and assign values.

This might not always be possible, eg. when a property has a polymorphic type. Provide hooks so that derived classes can override the parser.

Use ES6 Symbols for that.

There is a typo in README.md:

Typo: At this date (5015-07-18) only Chrome supports Object.observe.

Avers.define* functions will get a new optional argument which will be used as the default value. The absence of the optional argument will make the field nullable. If a default value is provided and the field is null, then Avers.migrateObject will initialize the property with a clone of the default value.

TODO: figure out what to do for variant properties.

Examples:

// Primitive property:
var default = 'default value';
Avers.defineProperty(Foo, 'field', default);

// Object property:
var default = Avers.mk(Bar, { test: 'one' });
Avers.defineObject(Foo, 'field', Bar, default);

// Variant property:
var default = Avers.mk(Bar, { test: 'one' });
Avers.defineVariant(Foo, 'type', 'content', { bar: Bar, baz: Baz }, default);

fetch()-initiated requests can be aborted: fetch(url).then(req => { req.cancel(); })