Restore MarkdownSerializerState + add test

__tests__/serialize.spec.js

@@ -49,6 +49,10 @@ describe('serialize', () => {
             expect(serialize('My <strong> example </strong>')).toEqual('My  **example** ');
             expect(serialize('My <em> example </em>')).toEqual('My  *example* ');
         });
+        test('trim inline', () => {
+            expect(serialize('My<strong>, example</strong>')).toEqual('My, **example**');
+            expect(serialize('My<em>. example</em>')).toEqual('My. *example*');
+        });
     });
     describe('nodes', () => {
         test('paragraph', () => {

__tests__/util.spec.js

@@ -0,0 +1,22 @@
+import { shiftDelim, trimInline } from "../src/util/markdown";
+
+describe('util' ,() => {
+    describe('trimInline', () => {
+        test('full', () => {
+            expect(trimInline('*abcde*', 0, 6)).toEqual('*abcde*');
+        });
+        test('left', () => {
+            expect(trimInline('a*, bcde*', '*', 1, 8)).toEqual('a, *bcde*');
+        });
+        test('right', () => {
+            expect(trimInline('*abcd ,*e', '*', 0, 7)).toEqual('*abcd* ,e');
+        });
+        test('meet', () => {
+            expect(trimInline('e*,,*e', '*', 1, 4)).toEqual('e,,e');
+        });
+    });
+    test('shiftDelim', () => {
+        expect(shiftDelim('e**abcd', '**', 1, 1)).toEqual('ea**bcd');
+        expect(shiftDelim('e**abcd', '**', 1, -1)).toEqual('**eabcd');
+    })
+})

example/src/content.md

@@ -21,6 +21,7 @@ ___
 
 ***
 
+Aenean ut eros et nisl sagittis vestibulum. Donec vitae orci sed dolor rutrum auctor. Vestibulum rutrum, mi nec elementum vehicula, eros quam gravida nisl, id fringilla neque ante vel mi.
 
 ## Emphasis
 

src/serialize/MarkdownSerializer.js

@@ -1,4 +1,4 @@
-import { MarkdownSerializerState } from "prosemirror-markdown";
+import { MarkdownSerializerState } from './state';
 import HTMLMark from "../extensions/marks/html";
 import HTMLNode from "../extensions/nodes/html";
 import { getMarkdownSpec } from "../util/extensions";

src/serialize/state.js

@@ -0,0 +1,55 @@
+import { MarkdownSerializerState as BaseMarkdownSerializerState } from "prosemirror-markdown";
+import { trimInline } from "../util/markdown";
+
+
+/**
+ * Override default MarkdownSerializerState to:
+ * - handle commonmark delimiters (https://spec.commonmark.org/0.29/#left-flanking-delimiter-run)
+ */
+export class MarkdownSerializerState extends BaseMarkdownSerializerState {
+
+    constructor(nodes, marks, options) {
+        super(nodes, marks, options ?? {});
+        this.inlines = [];
+    }
+
+    render(node, parent, index) {
+        super.render(node, parent, index);
+        const top = this.inlines[this.inlines.length - 1];
+        if(top?.start && top?.end) {
+            const { delimiter, start, end } = this.normalizeInline(top);
+            this.out = trimInline(this.out, delimiter, start, end);
+            this.inlines.pop();
+        }
+    }
+
+    markString(mark, open, parent, index) {
+        const info = this.marks[mark.type.name]
+        if(info.expelEnclosingWhitespace) {
+            if(open) {
+                this.inlines.push({
+                    start: this.out.length,
+                    delimiter: info.open,
+                });
+            } else {
+                const top = this.inlines.pop();
+                this.inlines.push({
+                    ...top,
+                    end: this.out.length,
+                });
+            }
+        }
+        return super.markString(mark, open, parent, index);
+    }
+
+    normalizeInline(inline) {
+        let { start, end } = inline;
+        while(this.out.charAt(start).match(/\s/)) {
+            start++;
+        }
+        return {
+            ...inline,
+            start,
+        }
+    }
+}

src/util/markdown.js

@@ -0,0 +1,54 @@
+import markdownit from 'markdown-it';
+
+
+function scanDelims(text, pos) {
+    const state = new (markdownit().inline.State)(text, null, null, []);
+    return state.scanDelims(pos, true);
+}
+
+export function shiftDelim(text, delim, start, offset) {
+    let res = text.substring(0, start) + text.substring(start + delim.length);
+    res = res.substring(0, start + offset) + delim + res.substring(start + offset);
+    return res;
+}
+
+function trimStart(text, delim, from, to) {
+    let pos = from, res = text;
+    while(pos < to) {
+        if(scanDelims(res, pos).can_open) {
+            break;
+        }
+        res = shiftDelim(res, delim, pos, 1);
+        pos++;
+    }
+    return { text: res, from: pos, to }
+}
+
+function trimEnd(text, delim, from, to) {
+    let pos = to, res = text;
+    while(pos > from) {
+        if(scanDelims(res, pos).can_close) {
+            break;
+        }
+        res = shiftDelim(res, delim, pos, -1);
+        pos--;
+    }
+    return { text: res, from, to: pos }
+}
+
+export function trimInline(text, delim, from, to) {
+    let state = {
+        text,
+        from,
+        to,
+    }
+
+    state = trimStart(state.text, delim, state.from, state.to);
+    state = trimEnd(state.text, delim, state.from, state.to);
+
+    if(state.to - state.from < delim.length + 1) {
+        state.text = state.text.substring(0, state.from) + state.text.substring(state.to + delim.length);
+    }
+
+    return state.text;
+}