trey · March 20, 2021 13:40 · Mar 20, 2021 · Mar 20, 2021 · Mar 20, 2021
diff --git a/gistfile1.txt → markdown-autocomplete.js b/gistfile1.txt → markdown-autocomplete.js
diff --git a/gistfile1.txt b/gistfile1.txt
@@ -0,0 +1,44 @@
+const $textarea = $('textarea');
+const ulRegex = /^- .+/;
+const olRegex = /^\d+\. .+/;
+const olNumberRegex = /^\d+/;
+const emptyLiRegex = /^(-|(\d+\.)) $/;
+const emptyOlLiRegex = /^\d+\. $/;
+
+$textarea.on('keyup', e => {
+    const $this = $(e.target);
+
+    if (e.which === 13) {
+        // `13` is the return key.
+        const cursorPosition = $this.prop('selectionStart');
+        const everything = $this.val();
+        const beforeCursor = everything.slice(0, cursorPosition);
+        const afterCursor = everything.slice(cursorPosition);
+        let lines = beforeCursor.split('\n');
+        const lastLine = lines[lines.length - 2];
+
+        if (lastLine.match(ulRegex)) {
+            $this.val(beforeCursor + '- ' + afterCursor);
+            $this[0].setSelectionRange(cursorPosition + 2, cursorPosition + 2);
+        }
+
+        if (lastLine.match(olRegex)) {
+            let nextNumber = Number(olNumberRegex.exec(lastLine)[0]) + 1;
+            let numberLength = nextNumber.toString().length + 2;
+            $this.val(beforeCursor + `${nextNumber}. ` + afterCursor);
+            $this[0].setSelectionRange(cursorPosition + numberLength, cursorPosition + numberLength);
+        }
+
+        if (lastLine.match(emptyLiRegex)) {
+            let offset = 3;
+
+            if (lastLine.match(emptyOlLiRegex)) {
+                offset += Number(olNumberRegex.exec(lastLine)[0].length);
+            }
+
+            lines.splice(-2, 1);
+            $this.val(lines.join('\n') + '' + afterCursor);
+            $this[0].setSelectionRange(cursorPosition - offset, cursorPosition - offset);
+        }
+    }
+});