Add insertNewlineContinueMarkupCommand

FEATURE: Add a variant of `insertNewlineContinueMarkup` that supports configuration
options.

Closes codemirror/dev#1628

Author: marijnh

README.md

@@ -115,6 +115,23 @@ trailing whitespace and list markers are removed from that line.</p>
 not be used as the only binding for Enter (even in a Markdown
 document, HTML and code regions might use a different language).</p>
 </dd>
+<dt id="user-content-insertnewlinecontinuemarkupcommand">
+  <code><strong><a href="#user-content-insertnewlinecontinuemarkupcommand">insertNewlineContinueMarkupCommand</a></strong>(<a id="user-content-insertnewlinecontinuemarkupcommand^config" href="#user-content-insertnewlinecontinuemarkupcommand^config">config</a>&#8288;?: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object">Object</a> = {}) → <a href="https://codemirror.net/docs/ref#state.StateCommand">StateCommand</a></code></dt>
+
+<dd><p>Returns a command like
+<a href="#user-content-insertnewlinecontinuemarkup"><code>insertNewlineContinueMarkup</code></a>,
+allowing further configuration.</p>
+<dl><dt id="user-content-insertnewlinecontinuemarkupcommand^config">
+  <code><strong><a href="#user-content-insertnewlinecontinuemarkupcommand^config">config</a></strong></code></dt>
+
+<dd><dl><dt id="user-content-insertnewlinecontinuemarkupcommand^config.nontightlists">
+  <code><strong><a href="#user-content-insertnewlinecontinuemarkupcommand^config.nontightlists">nonTightLists</a></strong>&#8288;?: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean">boolean</a></code></dt>
+
+<dd><p>By default, when pressing enter in a blank second item in a
+tight (no blank lines between items) list, the command will
+insert a blank line above that item, starting a non-tight list.
+Set this to false to disable this behavior.</p>
+</dd></dl></dd></dl></dd>
 <dt id="user-content-deletemarkupbackward">
   <code><strong><a href="#user-content-deletemarkupbackward">deleteMarkupBackward</a></strong>: <a href="https://codemirror.net/docs/ref#state.StateCommand">StateCommand</a></code></dt>
 

src/README.md

@@ -42,6 +42,8 @@ const view = new EditorView({
 
 @insertNewlineContinueMarkup
 
+@insertNewlineContinueMarkupCommand
+
 @deleteMarkupBackward
 
 @markdownKeymap

src/commands.ts

@@ -92,16 +92,16 @@ function normalizeIndent(content: string, state: EditorState) {
   return space + content.slice(blank)
 }
 
-/// This command, when invoked in Markdown context with cursor
-/// selection(s), will create a new line with the markup for
-/// blockquotes and lists that were active on the old line. If the
-/// cursor was directly after the end of the markup for the old line,
-/// trailing whitespace and list markers are removed from that line.
-///
-/// The command does nothing in non-Markdown context, so it should
-/// not be used as the only binding for Enter (even in a Markdown
-/// document, HTML and code regions might use a different language).
-export const insertNewlineContinueMarkup: StateCommand = ({state, dispatch}) => {
+/// Returns a command like
+/// [`insertNewlineContinueMarkup`](#lang-markdown.insertNewlineContinueMarkup),
+/// allowing further configuration.
+export const insertNewlineContinueMarkupCommand = (config: {
+  /// By default, when pressing enter in a blank second item in a
+  /// tight (no blank lines between items) list, the command will
+  /// insert a blank line above that item, starting a non-tight list.
+  /// Set this to false to disable this behavior.
+  nonTightLists?: boolean
+} = {}): StateCommand => ({state, dispatch}) => {
   let tree = syntaxTree(state), {doc} = state
   let dont = null, changes = state.changeByRange(range => {
     if (!range.empty || !markdownLanguage.isActiveAt(state, range.from, -1) && !markdownLanguage.isActiveAt(state, range.from, 1))
@@ -119,7 +119,8 @@ export const insertNewlineContinueMarkup: StateCommand = ({state, dispatch}) =>
       let first = inner.node.firstChild!, second = inner.node.getChild("ListItem", "ListItem")
       // Not second item or blank line before: delete a level of markup
       if (first.to >= pos || second && second.to < pos ||
-          line.from > 0 && !/[^\s>]/.test(doc.lineAt(line.from - 1).text)) {
+          line.from > 0 && !/[^\s>]/.test(doc.lineAt(line.from - 1).text) ||
+          config.nonTightLists === false) {
         let next = context.length > 1 ? context[context.length - 2] : null
         let delTo, insert = ""
         if (next && next.item) { // Re-add marker for the list at the next level
@@ -172,6 +173,17 @@ export const insertNewlineContinueMarkup: StateCommand = ({state, dispatch}) =>
   return true
 }
 
+/// This command, when invoked in Markdown context with cursor
+/// selection(s), will create a new line with the markup for
+/// blockquotes and lists that were active on the old line. If the
+/// cursor was directly after the end of the markup for the old line,
+/// trailing whitespace and list markers are removed from that line.
+///
+/// The command does nothing in non-Markdown context, so it should
+/// not be used as the only binding for Enter (even in a Markdown
+/// document, HTML and code regions might use a different language).
+export const insertNewlineContinueMarkup = insertNewlineContinueMarkupCommand()
+
 function isMark(node: SyntaxNode) {
   return node.name == "QuoteMark" || node.name == "ListMark"
 }

src/index.ts

@@ -5,8 +5,8 @@ import {Completion, CompletionContext} from "@codemirror/autocomplete"
 import {MarkdownExtension, MarkdownParser, parseCode} from "@lezer/markdown"
 import {html, htmlCompletionSource} from "@codemirror/lang-html"
 import {commonmarkLanguage, markdownLanguage, mkLang, getCodeParser, headerIndent} from "./markdown"
-import {insertNewlineContinueMarkup, deleteMarkupBackward} from "./commands"
-export {commonmarkLanguage, markdownLanguage, insertNewlineContinueMarkup, deleteMarkupBackward}
+import {insertNewlineContinueMarkup, insertNewlineContinueMarkupCommand, deleteMarkupBackward} from "./commands"
+export {commonmarkLanguage, markdownLanguage, insertNewlineContinueMarkup, insertNewlineContinueMarkupCommand, deleteMarkupBackward}
 
 /// A small keymap with Markdown-specific bindings. Binds Enter to
 /// [`insertNewlineContinueMarkup`](#lang-markdown.insertNewlineContinueMarkup)