Promise (From "Promise") ((TOP))
The bill permits students to enroll on a part-time or full-time basis, but students must maintain satisfactory academic progress toward completion of the promise-eligible program and complete the program within 36 months from the first award. Upon completion of the program, students must reside and work in Kansas for a minimum of two consecutive years or enroll in a Kansas institution of higher education and subsequently reside and work in Kansas for a minimum of two consecutive years.
Promise (From "Promise")
dojo/promise/Promise defines the Dojo Promises API and is an abstract class. dojo/Deferred for example implements the class. The class is intended to encapsulate communication between asynchronous threads.
The main advantage of using a Promise in JavaScript is that a user can assign callback functions to the promises in case of a rejection or fulfillment of a Promise, also by using promises one can easily handle the control flow of all the Asynchronous events or data upcoming. As the name suggests a promise is either kept or broken. So, a promise is either completed(kept) or rejected(broken).
The new Promise() constructor returns a promise object. As the executor function needs to handle async operations, the returned promise object should be capable of informing when the execution has been started, completed (resolved) or retuned with error (rejected).
A Promise uses an executor function to complete a task (mostly asynchronously). A consumer function (that uses an outcome of the promise) should get notified when the executor function is done with either resolving (success) or rejecting (error).
First, let us create a generic function that accepts a PokeAPI URL as argument and returns a Promise. If the API call is successful, a resolved promise is returned. A rejected promise is returned for any kind of errors.
You can use this handler method to handle errors (rejections) from promises. The syntax of passing null as the first argument to the .then() is not a great way to handle errors. So we have .catch() to do the same job with some neat syntax:
If we throw an Error like new Error("Something wrong!") instead of calling the reject from the promise executor and handlers, it will still be treated as a rejection. It means that this will be caught by the .catch handler method.
The .finally() handler performs cleanups like stopping a loader, closing a live connection, and so on. The finally() method will be called irrespective of whether a promise resolves or rejects. It passes through the result or error to the next handler which can call a .then() or .catch() again.
When the first .then method returns a value, the next .then method can receive that. The second one can now pass to the third .then() and so on. This forms a chain of .then methods to pass the promises down. This phenomenon is called the Promise Chain.
Here we first get a promise resolved and then extract the URL to reach the first Pokémon. We then return that value and it will be passed as a promise to the next .then() handler function. Hence the output,
This method waits for all the promises to resolve and returns the array of promise results. If any of the promises reject or execute to fail due to an error, all other promise results will be ignored.
Promise.any([promises]) - Similar to the all() method, .any() also accepts an array of promises to execute them in parallel. This method doesn't wait for all the promises to resolve. It is done when any one of the promises is settled.
romise.allSettled([promises]) - This method waits for all promises to settle(resolve/reject) and returns their results as an array of objects. The results will contain a state (fulfilled/rejected) and value, if fulfilled. In case of rejected status, it will return a reason for the error.
Sure, let's do it. Let us assume that the query method will return a promise. Here is an example query() method. In real life, this method may talk to a database and return results. In this case, it is very much hard-coded but serves the same purpose.
Next, you should learn about the async function in JavaScript which simplifies things further. The concept of JavaScript promises is best learned by writing small examples and building on top of them.
While a deferred represents the computation itself, a Promise representsthe result of that computation. Thus, each deferred has a promise that acts asa placeholder for its actual result.
Rejects the promise returned by promise(), signalling that the deferred'scomputation failed.All consumers are notified by having $onRejected (which they registered via$promise->then()) called with $reason.
All functions working on promise collections (like all(), race(), some()etc.) support cancellation. This means, if you call cancel() on the returnedpromise, all promises in the collection are cancelled. If the collection itselfis a promise which resolves to an array, this promise is also cancelled.
Note: The promise returned is always a promise implementingExtendedPromiseInterface. If you pass in a custompromise which only implements PromiseInterface, thispromise will be assimilated to a extended promise following $promiseOrValue.
Returns a promise that will resolve only once all the items in$promisesOrValues have resolved. The resolution value of the returned promisewill be an array containing the resolution values of each of the items in$promisesOrValues.
Returns a promise that will resolve when $howMany of the supplied items in$promisesOrValues resolve. The resolution value of the returned promisewill be an array of length $howMany containing the resolution values of thetriggering items.
The returned promise will reject if it becomes impossible for $howMany itemsto resolve (that is, when (count($promisesOrValues) - $howMany) + 1 itemsreject). The rejection value will be an array of(count($promisesOrValues) - $howMany) + 1 rejection reasons.
Traditional reduce function, similar to array_reduce(), but input may containpromises and/or values, and $reduceFunc may return either a value or apromise, and $initialValue may be a promise or a value for the startingvalue.
A few simple examples to show how the mechanics of Promises/A forwarding works.These examples are contrived, of course, and in real usage, promise chains willtypically be spread across several function calls, or even several levels ofyour application architecture.
Similarly, when you handle a rejected promise, to propagate the rejection,"rethrow" it by either returning a rejected promise, or actually throwing(since promise translates thrown exceptions into rejections)
In addition to transforming a value, then() allows you to recover from, orpropagate intermediate errors. Any errors that are not handled will be caughtby the promise machinery and used to reject the promise returned by then().
This is a implementation of Promises in Python. It is a super set ofPromises/A+ designed to have readable, performant code and to providejust the extensions that are absolutely necessary for using promises inPython.
The example below shows how you can load the promise library. It thendemonstrates creating a promise from scratch. You simply callPromise(fn). There is a complete specification for what is returnedby this method inPromises/A+.
resolve should be called with a single argument. If it is calledwith a non-promise value then the promise is fulfilled with thatvalue. If it is called with a promise (A) then the returned promisetakes on the state of that new promise (A).reject should be called with a single argument. The returnedpromise will be rejected with that argument.
Class MethodsThese methods are invoked by calling Promise.methodName.
Converts values and foreign promises into Promises/A+ promises. If youpass it a value then it returns a Promise for that value. If you pass itsomething that is close to a promise (such as a jQuery attempt at apromise) it returns a Promise that takes on the state of value(rejected or fulfilled).
A special function that takes a dictionary of promises and turns theminto a promise for a dictionary of values. In other words, this turns andictionary of promises for values into a promise for a dictionary ofvalues.
The call to .then also returns a promise. If the handler that iscalled returns a promise, the promise returned by .then takes on thestate of that returned promise. If the handler that is called returns avalue that is not a promise, the promise returned by .then will befulfilled with that value. If the handler that is called throws anexception then the promise returned by .then is rejected with thatexception.
Mikael Boghosian is an apothecary who lives in the small Armenian village of Siroun in the southeast part of Turkey, within the Ottoman Empire. In order to help pay the expenses for medical school, he promises to marry Maral, the daughter of an affluent neighbor, receiving 400 gold coins as a dowry. This allows him to travel to Constantinople and attend the Imperial School of Medicine.
We hope that this tool will be of use to numerous Promise stakeholders, including researchers, policymakers, educators, the media, and members of the public. The entire database is available on request, and we welcome feedback and corrections; please email promisedatabase@upjohn.org.
Beginning with the announcement of the Kalamazoo Promise in 2005, the Upjohn Institute has been tracking the emergence of Promise programs in communities around the nation. This material was available on our website in tabular form for many years. As the Promise movement has grown and variations in program structure have emerged, the Institute has sought to categorize and classify Promise programs by their various attributes. This database, which currently includes 216 entries, is a product of our data collection and analysis efforts. By providing data and analytical tools in an interactive, searchable format, we hope to make it easier for stakeholders, policymakers, media, researchers, and other interested individuals to learn about the Promise movement in its many different forms. The full database is available on request by writing to promisedatabase@upjohn.org 041b061a72