SimpleChatTCRV:Markdown:List: Allow split line items

If the split lines dont have any empty lines inbetween and also
remain within the block area of the list item which they belong
to, then the split line will be appended to the corresponding
list item, ELSE a new list item will be created.

To help with same a generic keyed empty lines tracker logic has
been added.

TODO: Account similar semantic wrt paragraph related split lines

tools/server/public_simplechat/docs/changelog.md

@@ -300,7 +300,11 @@ Chat Session specific settings
   * the user can change the default behaviour of tools being disabled and sliding window of 1
   * program restart will reset these back to the default
 * Ui module cleanup to avoid duplicated/unneeded boiler plates, including using updated jsdoc annotations
-* A simple minded basic Markdown to Html logic
+* A simple minded basic Markdown to Html logic with support for
+  * headings
+  * lists (ordered, unordered, intermixed at diff leves)
+  * tables
+  * fenced code blocks
 
 
 ## ToDo

tools/server/public_simplechat/typemd.mjs

@@ -28,7 +28,7 @@ export class MarkDown {
                 /** @type {Array<string>} */
                 endType: [],
             },
-            /** @type {Object<string, string>} */
+            /** @type {Object<string, number>} */
             empty: {
             }
         }
@@ -40,6 +40,23 @@ export class MarkDown {
         this.html = ""
     }
 
+    /**
+     * @param {string} key
+     * @param {string} line
+     */
+    empty_tracker(key, line) {
+        if (this.in.empty[key] == undefined) {
+            this.in.empty[key] = 0
+        }
+        let prev = this.in.empty[key]
+        if (line.trim().length == 0) {
+            this.in.empty[key] += 1
+        } else {
+            this.in.empty[key] = 0
+        }
+        return {prev: prev, cur: this.in.empty[key]}
+    }
+
     unwind_list() {
         while (true) {
             let popped = this.in.list.endType.pop()
@@ -52,10 +69,19 @@ export class MarkDown {
     }
 
     /**
-     * Process list one line at a time
+     * Process list one line at a time.
+     * * Account for ordered lists as well as unordered lists, including intermixing of the lists.
+     *   at different list hierarchy levels.
+     * * Allow a list item line to be split into multiple lines provided the split lines retain
+     *   the same or more line offset compared to the starting line of the item to which they belong.
+     *   * if there is a empty line in between, then the new line will be treated as a new item.
+     * * allows for empty lines inbetween items.
+     *   * currently there is no limit on the number of empty lines.
+     *     but may bring in a limit later.
      * @param {string} line
      */
     process_list(line) {
+        let emptyTracker = this.empty_tracker("list", line)
         // spaces followed by - or + or * followed by a space and actual list item
         let matchList = line.match(/^([ ]*)([-+*]|[a-zA-Z0-9]\.)[ ](.*)$/);
         if (matchList != null) {
@@ -89,7 +115,7 @@ export class MarkDown {
             return true
         } else {
             if (this.in.list.offsets.length > 0) {
-                if (line.trim().length == 0) {
+                if (emptyTracker.cur > 0) {
                     return true
                 }
                 let matchOffset = line.match(/^([ ]*)(.*)$/);
@@ -100,7 +126,12 @@ export class MarkDown {
                 if (matchOffset[1].length < lastOffset) {
                     return false
                 }
-                this.html += `<li>${matchOffset[2]}</li>\n`
+                if ((emptyTracker.prev != 0) || (!this.html.endsWith("</li>\n"))) {
+                    this.html += `<li>${matchOffset[2]}</li>\n`
+                } else {
+                    let html = this.html
+                    this.html = `${html.slice(0,html.length-"</li>\n".length)} ${matchOffset[2]}</li>\n`
+                }
                 return true
             }
         }