From ab7d17509e0431706a1f066d2350a2e190ba9083 Mon Sep 17 00:00:00 2001
From: sibiraj-s <dev.sibiraj@outlook.com>
Date: Fri, 9 Jul 2021 00:14:34 +0530
Subject: [PATCH] feat: add markdown shortcuts for bold and italics

---
 projects/ngx-editor/helpers/markInputRule.ts  | 28 +++++++++++++++++++
 projects/ngx-editor/helpers/public_api.ts     |  1 +
 projects/ngx-editor/src/lib/defaultPlugins.ts | 14 +++++++++-
 3 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 projects/ngx-editor/helpers/markInputRule.ts

diff --git a/projects/ngx-editor/helpers/markInputRule.ts b/projects/ngx-editor/helpers/markInputRule.ts
new file mode 100644
index 00000000..ee796330
--- /dev/null
+++ b/projects/ngx-editor/helpers/markInputRule.ts
@@ -0,0 +1,28 @@
+import { InputRule } from "prosemirror-inputrules"
+import { MarkType } from "prosemirror-model"
+
+export const markInputRule = (regexp: RegExp, markType: MarkType, attrs: Record<string, unknown>): InputRule => {
+
+  return new InputRule(regexp, (state, match, start, end) => {
+
+    const tr = state.tr
+
+    if (match[2]) {
+      const textStart = start + match[0].indexOf(match[2])
+      const textEnd = textStart + match[2].length
+
+      if (textEnd < end) {
+        tr.delete(textEnd, end)
+      }
+
+      if (textStart > start) {
+        tr.delete(start, textStart)
+      }
+
+      end = start + match[2].length
+    }
+    return tr.addMark(start, end, markType.create(attrs))
+  })
+}
+
+export default markInputRule
diff --git a/projects/ngx-editor/helpers/public_api.ts b/projects/ngx-editor/helpers/public_api.ts
index b7fb204d..cc4fa722 100644
--- a/projects/ngx-editor/helpers/public_api.ts
+++ b/projects/ngx-editor/helpers/public_api.ts
@@ -5,3 +5,4 @@ export * from './getSelectionMarks';
 export * from './bubblePosition';
 export * from './getSelectionNodes';
 export * from './markApplies';
+export * from './markInputRule';
diff --git a/projects/ngx-editor/src/lib/defaultPlugins.ts b/projects/ngx-editor/src/lib/defaultPlugins.ts
index 6859166c..9723656f 100644
--- a/projects/ngx-editor/src/lib/defaultPlugins.ts
+++ b/projects/ngx-editor/src/lib/defaultPlugins.ts
@@ -1,4 +1,4 @@
-import { NodeType, Schema } from 'prosemirror-model';
+import { MarkType, NodeType, Schema } from 'prosemirror-model';
 import { Plugin } from 'prosemirror-state';
 import { keymap } from 'prosemirror-keymap';
 import { toggleMark, baseKeymap, chainCommands, exitCode } from 'prosemirror-commands';
@@ -9,6 +9,8 @@ import {
   smartQuotes, emDash, ellipsis, InputRule
 } from 'prosemirror-inputrules';
 
+import { markInputRule } from 'ngx-editor/helpers';
+
 interface Options {
   history: boolean;
   keyboardShortcuts: boolean;
@@ -70,12 +72,22 @@ const headingRule = (nodeType: NodeType, maxLevel: number): InputRule => {
   );
 };
 
+const boldRule = (markType: MarkType): InputRule => {
+  return markInputRule(/(?:^|\s)((?:\*\*|__)((?:[^*_]+))(?:\*\*|__))$/, markType, {})
+}
+
+const emRule = (markType: MarkType): InputRule => {
+  return markInputRule(/(?:^|\s)((?:\*|_)((?:[^*_]+))(?:\*|_))$/, markType, {})
+}
+
 // : (Schema) → Plugin
 // A set of input rules for creating the basic block quotes, lists,
 // code blocks, and heading.
 const buildInputRules = (schema: Schema): Plugin => {
   const rules = smartQuotes.concat(ellipsis, emDash);
 
+  rules.push(boldRule(schema.marks.strong));
+  rules.push(emRule(schema.marks.em));
   rules.push(blockQuoteRule(schema.nodes.blockquote));
   rules.push(orderedListRule(schema.nodes.ordered_list));
   rules.push(bulletListRule(schema.nodes.bullet_list));