Remove additional exports of breakpoint symbols.

Restore typedef entries in `Breakpoint` component.
Generate type definitions for `constants.js` and `breakpointObserver.js`.
Validate size passed to `smallerThan`/`largerThan`.
Document `breakpointObserver`/`breakpoints`.
Fix `Breakpoint` component docs/example.

docs/src/COMPONENT_API.json

@@ -403,7 +403,18 @@
           "detail": "{ size: BreakpointSize; breakpointValue: BreakpointValue; }"
         }
       ],
-      "typedefs": []
+      "typedefs": [
+        {
+          "type": "\"sm\" | \"md\" | \"lg\" | \"xlg\" | \"max\"",
+          "name": "BreakpointSize",
+          "ts": "type BreakpointSize = \"sm\" | \"md\" | \"lg\" | \"xlg\" | \"max\""
+        },
+        {
+          "type": "320 | 672 | 1056 | 1312 | 1584",
+          "name": "BreakpointValue",
+          "ts": "type BreakpointValue = 320 | 672 | 1056 | 1312 | 1584"
+        }
+      ]
     },
     {
       "moduleName": "Button",

docs/src/pages/components/Breakpoint.svx

@@ -22,6 +22,14 @@ This utility component uses the [Window.matchMedia API](https://developer.mozill
 
 Bind to the `size` prop to determine the current breakpoint size. Possible values include: `"sm" | "md" | "lg" | "xlg" | "max"`.
 
-The `"on:match"` event will fire only when a breakpoint change event occurs (e.g., the browser width is resized).
+The `"on:change"` event will fire when the size is initially determined and when a breakpoint change event occurs (e.g., the browser width is resized).
 
-<FileSource src="/framed/Breakpoint/Breakpoint" />
+<FileSource src="/framed/Breakpoint/Breakpoint" />
+
+### Store and Breakpoint Values
+
+As an alternative to the component, `breakpointObserver` can be used to get the current size as a Svelte store. The store has two additional functions which create derived stores that return a `boolean` indicating whether the size is smaller/larger than a certain breakpoint.
+
+There also exists a `breakpoints` dictionary mapping from `BreakpointSize` to `BreakpointValue`.
+
+<FileSource src="/framed/Breakpoint/BreakpointObserver" />

docs/src/pages/framed/Breakpoint/Breakpoint.svelte

@@ -5,13 +5,13 @@
   let events = [];
 </script>
 
-<Breakpoint bind:size on:match="{(e) => (events = [...events, e.detail])}" />
+<Breakpoint bind:size on:change="{(e) => (events = [...events, e.detail])}" />
 
 <p>Resize the width of your browser.</p>
 <h6>Breakpoint size</h6>
 <h1>{size}</h1>
 
-<h6>on:match</h6>
+<h6>on:change</h6>
 <pre>
   {JSON.stringify(events, null, 2)}
 </pre>

docs/src/pages/framed/Breakpoint/BreakpointObserver.svelte

@@ -0,0 +1,15 @@
+<script>
+  import {
+    breakpointObserver,
+    breakpoints,
+  } from "carbon-components-svelte/src/Breakpoint";
+
+  const size = breakpointObserver();
+  const smaller = size.smallerThan("md");
+  const larger = size.largerThan("md");
+</script>
+
+<p>Current breakpoint size: {$size}</p>
+<p>Current breakpoint value: {breakpoints[$size]}px</p>
+<p>Smaller than medium: {$smaller}</p>
+<p>Larger than medium: {$larger}</p>