How to monitor events when jumping between WeChat applet pages

We know that the mini program provides four mechanisms to change the view, including opening a new page, page redirection, page return, and tabBar switching. It hosts the page. life cycle, and provides corresponding life cycle events for the application to facilitate business processing at each stage of the application, but there is no corresponding event mechanism for jumping between pages, for example -

1. Page A opens secondary page B. Page B has done some operations, and it needs to notify page A to do the corresponding processing.
2. Carry some data from page B and return to page A

The above two scenarios are very common and boil down to page How to interact conveniently? Of course, we can achieve the goal by passing parameters or global data objects through page jumps, but there are some restrictions on use (converting parameters or maintaining global objects)!

So the event mechanism is used to solve this problem in the elong applet project . We rewrote navigateToAPI. After page A calls this interface to jump to the page, the method returns an event object event to page A. This object can register custom events, and the target page (page B) can follow the business The demand triggers the event response, and the relevant data is passed as a parameter to the listening callback.
A Page

##BPage

##API

##Event

##Part of the code is as follows:

    Page({
        data: {
            userInfo: {}
        },
        navigateToHttp: function () {
            var event = api.Navigate.go({
                url: '../http/index',
                params: {
                    name: 'billy'
                }
            });
            event.on("listok", function (params) {
                console.log(params)
            });
        },
        navigateToExternalComponent: function () {
            var event = api.Navigate.go({
                url: '../externalComponent/index'
            });
        },
        navigateToInternalComponent: function () {
            var event = api.Navigate.go({
                url: '../internalComponent/index'
            });
        },
        navigateToPartComponent: function (params) {
            var event = api.Navigate.go({
                url: '../partComponent/index'
            });
        },