Address new TypeScript warnings in core files, improve type definitions.

lib/md004.mjs

@@ -4,21 +4,9 @@ import { addErrorDetailIf } from "../helpers/helpers.cjs";
 import { getDescendantsByType, getParentOfType } from "../helpers/micromark-helpers.cjs";
 import { filterByTypesCached } from "./cache.mjs";
 
-const markerToStyle = {
-  "-": "dash",
-  "+": "plus",
-  "*": "asterisk"
-};
-const styleToMarker = {
-  "dash": "-",
-  "plus": "+",
-  "asterisk": "*"
-};
-const differentItemStyle = {
-  "dash": "plus",
-  "plus": "asterisk",
-  "asterisk": "dash"
-};
+const markerToStyle = (/** @type {string} */ marker) => (marker === "-") ? "dash" : ((marker === "+") ? "plus" : "asterisk");
+const styleToMarker = (/** @type {string} */ style) => (style === "dash") ? "-" : ((style === "plus") ? "+" : "*");
+const differentItemStyle = (/** @type {string} */ style) => (style === "dash") ? "plus" : ((style === "plus") ? "asterisk" : "dash");
 const validStyles = new Set([
   "asterisk",
   "consistent",
@@ -36,6 +24,7 @@ export default {
   "function": function MD004(params, onError) {
     const style = String(params.config.style || "consistent");
     let expectedStyle = validStyles.has(style) ? style : "dash";
+    /** @type {("asterisk"|"dash"|"plus")[]} */
     const nestingStyles = [];
     for (const listUnordered of filterByTypesCached([ "listUnordered" ])) {
       let nesting = 0;
@@ -49,12 +38,12 @@ export default {
       }
       const listItemMarkers = getDescendantsByType(listUnordered, [ "listItemPrefix", "listItemMarker" ]);
       for (const listItemMarker of listItemMarkers) {
-        const itemStyle = markerToStyle[listItemMarker.text];
+        const itemStyle = markerToStyle(listItemMarker.text);
         if (style === "sublist") {
           if (!nestingStyles[nesting]) {
             nestingStyles[nesting] =
               (itemStyle === nestingStyles[nesting - 1]) ?
-                differentItemStyle[itemStyle] :
+                differentItemStyle(itemStyle) :
                 itemStyle;
           }
           expectedStyle = nestingStyles[nesting];
@@ -74,7 +63,7 @@ export default {
           {
             "editColumn": column,
             "deleteCount": length,
-            "insertText": styleToMarker[expectedStyle]
+            "insertText": styleToMarker(expectedStyle)
           }
         );
       }