The Object.observe() method was used for asynchronously observing the changes to an object. It provided a stream of changes in the order in which they occur. However, this API has been deprecated and removed from browsers. You can use the more general Proxy object instead.
The toLocaleString() method returns a string representing the object. This method is meant to be overridden by derived objects for locale-specific purposes.
The Object.unobserve() method was used to remove observers set by Object.observe(), but has been deprecated and removed from Browsers. You can use the more general Proxy object instead.
The goal of ParallelArray was to enable data-parallelism in web applications. The higher-order functions available on ParallelArray attempted to execute in parallel, though they may fall back to sequential execution if necessary. To ensure that your code executes in parallel, it is suggested that the functions should be limited to the parallelizable subset of JS that Firefox supports.
The Promise.all(iterable) method returns a promise that resolves when all of the promises in the iterable argument have resolved, or rejects with the reason of the first passed promise that rejects.
The Promise.race(iterable) method returns a promise that resolves or rejects as soon as one of the promises in the iterable resolves or rejects, with the value or reason from that promise.
The Promise.resolve(value) method returns a Promise object that is resolved with the given value. If the value is a thenable (i.e. has a "then" method), the returned promise will "follow" that thenable, adopting its eventual state; otherwise the returned promise will be fulfilled with the value.
The Proxy object is used to define custom behavior for fundamental operations (e.g. property lookup, assignment, enumeration, function invocation, etc).