I found a nice YouTube video (Inter-module Communication with Custom Events) by John Brock, on the topic of inter-module communication in Oracle JET, using the concept of event bubbling.
The above method proposed by John will certainly solve communication problems between two JET modules, between a JET module and a CCA and also between two CCAs, and is thus a highly useful one.
However, there is another quick method to establish connectivity between two JET web components (CCAs), and that is through the writeback feature. This is essentially a quick solution, and works only between CCAs in one page (or module).
The writeback feature essentially means that when a property of a CCA is changed, the changed value is communicated to the component which is hosting the CCA. A crude and high-level process diagram would be something like this:
The app-controller contains an observable, which is a writeback-enabled property of CCA1. When this property is updated on the CCA, the value is also updated on app-controller. The subscription handler of this observable updates a variable on CCA2. The same flow is applied from CCA2 to CCA1. Read the complete article here.
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