[experimental][unreviewed] Mobx8 cleanup per discussion

.changeset/remove-legacy-apis.md

@@ -0,0 +1,17 @@
+---
+"mobx": major
+"mobx-react-lite": patch
+---
+
+Removed a number of legacy APIs and their supporting internals.
+
+Removed from `mobx`:
+
+-   The top-level object API: `get`, `set`, `has`, `remove`, `keys`, `values`, `entries`, `ownKeys`. Use the native/instance equivalents instead (e.g. `map.get()`, `[...map.keys()]`, `Object.keys(obj)`, `"key" in obj`, `delete obj.key`).
+-   The interception/observation APIs: `intercept`, `observe`, `_interceptReads`, and the `spy` API. Use `autorun`/`reaction` to react to changes.
+-   The introspection APIs: `getDebugName`, `getDependencyTree`, `getObserverTree`.
+-   The `dehancer` mechanism (used internally by the removed `_interceptReads`; it also backed some mobx-state-tree integrations, which are no longer supported).
+
+All associated change-event interfaces (`I*WillChange` / `I*DidChange`), the `IInterceptable`/`IInterceptor`/`IListenable` interfaces, and the related internal machinery have been removed as well. The MobX devtools global hook (which depended on `spy`) has been removed. `MOBX_GLOBALS_VERSION` was bumped accordingly.
+
+`mobx-react-lite` no longer wires the removed `getDependencyTree` into `React.useDebugValue`.

docs/api.md

@@ -278,20 +278,6 @@ _Utilities that might make working with observable objects or computed values mo
 
 Attaches a global error listener, which is invoked for every error that is thrown from a _reaction_. This can be used for monitoring or test purposes.
 
-### `intercept`
-
-{🚀} Usage: `intercept(propertyName|array|object|Set|Map, listener)`
-<small>(<b>[further information](intercept-and-observe.md#intercept)</b>)</small>
-
-Intercepts changes before they are applied to an observable API. Returns a disposer function that stops the interception.
-
-### `observe`
-
-{🚀} Usage: `observe(propertyName|array|object|Set|Map, listener)`
-<small>(<b>[further information](intercept-and-observe.md#observe)</b>)</small>
-
-Low-level API that can be used to observe a single observable value. Returns a disposer function that stops the interception.
-
 ### `onBecomeObserved`
 
 {🚀} Usage: `onBecomeObserved(observable, property?, listener: () => void)`
@@ -343,61 +329,6 @@ Use it to change how MobX behaves as a whole.
 
 ---
 
-## Collection utilities {🚀}
-
-_They enable manipulating observable arrays, objects and Maps with the same generic API._
-
-### `values`
-
-{🚀} Usage: `values(array|object|Set|Map)`
-<small>(<b>[further information](collection-utilities.md)</b>)</small>
-
-Returns all values in the collection as an array.
-
-### `keys`
-
-{🚀} Usage: `keys(array|object|Set|Map)`
-<small>(<b>[further information](collection-utilities.md)</b>)</small>
-
-Returns all keys / indices in the collection as an array.
-
-### `entries`
-
-{🚀} Usage: `entries(array|object|Set|Map)`
-<small>(<b>[further information](collection-utilities.md)</b>)</small>
-
-Returns a `[key, value]` pair of every entry in the collection as an array.
-
-### `set`
-
-{🚀} Usage: `set(array|object|Map, key, value)`
-<small>(<b>[further information](collection-utilities.md)</b>)</small>
-
-Updates the collection.
-
-### `remove`
-
-{🚀} Usage: `remove(array|object|Map, key)`
-<small>(<b>[further information](collection-utilities.md)</b>)</small>
-
-Removes item from the collection.
-
-### `has`
-
-{🚀} Usage: `has(array|object|Map, key)`
-<small>(<b>[further information](collection-utilities.md)</b>)</small>
-
-Checks for membership in the collection.
-
-### `get`
-
-{🚀} Usage: `get(array|object|Map, key)`
-<small>(<b>[further information](collection-utilities.md)</b>)</small>
-
-Gets value from the collection with key.
-
----
-
 ## Introspection utilities {🚀}
 
 _Utilities that might come in handy if you want to inspect the internal state of MobX, or want to build cool tools on top of MobX._
@@ -462,34 +393,6 @@ Is this a boxed computed value, created using `computed(() => expr)`?
 
 Is this a computed property?
 
-### `spy`
-
-{🚀} Usage: `spy(eventListener)`
-<small>(<b>[further information](analyzing-reactivity.md#spy)</b>)</small>
-
-Registers a global spy listener that listens to all events that happen in MobX.
-
-### `getDebugName`
-
-{🚀} Usage: `getDebugName(reaction|array|Set|Map)` or `getDebugName(object|Map, propertyName)`
-<small>(<b>[further information](analyzing-reactivity.md#getdebugname)</b>)</small>
-
-Returns the (generated) friendly debug name for an observable or reaction.
-
-### `getDependencyTree`
-
-{🚀} Usage: `getDependencyTree(object, computedPropertyName)`
-<small>(<b>[further information](analyzing-reactivity.md#getdependencytree)</b>)</small>
-
-Returns a tree structure with all observables the given reaction / computation currently depends upon.
-
-### `getObserverTree`
-
-{🚀} Usage: `getObserverTree(array|Set|Map)` or `getObserverTree(object|Map, propertyName)`
-<small>(<b>[further information](analyzing-reactivity.md#getobservertree)</b>)</small>
-
-Returns a tree structure with all reactions / computations that are observing the given observable.
-
 ---
 
 ## Extending MobX {🚀}
@@ -509,7 +412,6 @@ Creates your own observable data structure and hooks it up to MobX. Used interna
 ### `getAtom`
 
 {🚀} Usage: `getAtom(thing, property?)`
-<small>(<b>[further information](analyzing-reactivity.md#getatom)</b>)</small>
 
 Returns the backing atom.
 

docs/computeds.md

@@ -210,7 +210,7 @@ This form of `computed` is not used very often, but in some cases where you need
 
 ### `name`
 
-This string is used as a debug name in the [Spy event listeners](analyzing-reactivity.md#spy) and [MobX developer tools](https://github.com/mobxjs/mobx-devtools).
+This string is used as a debug name in error messages and third-party developer tooling such as [mobx-log](https://github.com/kubk/mobx-log).
 
 ### `equals`