wtf is ember-composability-tools?

Ember-composability-tools is a toolkit for Ember developers who need to build components that don't produce normal web page elements. Instead of creating visible HTML, these components manage behind-the-scenes objects, like the layers and markers on an interactive map. This library provides the plumbing to make those kinds of components work smoothly. When you build nested components in Ember, the framework normally processes them from the bottom up, meaning inner components are handled before their outer parents. That causes a problem when a parent needs to exist before its children can be set up. For example, a map component must be created before you can add a tile layer or a marker to it. This library fixes that mismatch by giving developers new lifecycle hooks that trigger in a predictable, top-down order. It also gives parent and child components a way to find and communicate with each other, and it can capture the content written inside a component block, render it to an isolated piece of the page, and hand that off to a third-party library that needs full control over how and when it gets displayed. The project was originally built to power ember-leaflet, which brings interactive maps into Ember applications. A developer building a custom integration with a complex third-party library, where nesting order matters and the library manages its own layout, would reach for this tool to avoid reinventing that coordination logic. The README gives concrete map-based examples throughout: creating a map, then adding tiles and markers that need to attach to that map. The main tradeoff is that this is firmly Ember-specific infrastructure, aimed at a relatively advanced pattern that most basic applications won't need. The README is thorough about the three core problems being solved, but it doesn't go into detail about performance characteristics or edge cases. It's a focused utility extracted from a real project, intended for developers who find themselves facing the same architectural friction.