Escape markdown sequences (#2208)

* escape inline markdown character * fix typo * improve document around custom markdown plugin and add escape sequence utils * recover inline escape sequences on edit * remove escape sequences from plain text body * use `s` for strike-through instead of del * escape block markdown sequences * fix remove escape sequence was not removing all slashes from plain text * recover block sequences on edit
2025-02-21 19:19:24 +11:00
parent b63868bbb5
commit 7456c152b7
19 changed files with 764 additions and 476 deletions
@@ -0,0 +1 @@
+export * from './parser';
@@ -0,0 +1,40 @@
+import {
+  BoldRule,
+  CodeRule,
+  EscapeRule,
+  ItalicRule1,
+  ItalicRule2,
+  LinkRule,
+  SpoilerRule,
+  StrikeRule,
+  UnderlineRule,
+} from './rules';
+import { runInlineRule, runInlineRules } from './runner';
+import { InlineMDParser } from './type';
+
+const LeveledRules = [
+  BoldRule,
+  ItalicRule1,
+  UnderlineRule,
+  ItalicRule2,
+  StrikeRule,
+  SpoilerRule,
+  LinkRule,
+  EscapeRule,
+];
+
+/**
+ * Parses inline markdown text into HTML using defined rules.
+ *
+ * @param text - The markdown text to be parsed.
+ * @returns The parsed HTML or the original text if no markdown was found.
+ */
+export const parseInlineMD: InlineMDParser = (text) => {
+  if (text === '') return text;
+  let result: string | undefined;
+  if (!result) result = runInlineRule(text, CodeRule, parseInlineMD);
+
+  if (!result) result = runInlineRules(text, LeveledRules, parseInlineMD);
+
+  return result ?? text;
+};
@@ -0,0 +1,123 @@
+import { InlineMDRule } from './type';
+
+const MIN_ANY = '(.+?)';
+const URL_NEG_LB = '(?<!(https?|ftp|mailto|magnet):\\/\\/\\S*)';
+const ESC_NEG_LB = '(?<!\\\\)';
+
+const BOLD_MD_1 = '**';
+const BOLD_PREFIX_1 = `${ESC_NEG_LB}\\*{2}`;
+const BOLD_NEG_LA_1 = '(?!\\*)';
+const BOLD_REG_1 = new RegExp(
+  `${URL_NEG_LB}${BOLD_PREFIX_1}${MIN_ANY}${BOLD_PREFIX_1}${BOLD_NEG_LA_1}`
+);
+export const BoldRule: InlineMDRule = {
+  match: (text) => text.match(BOLD_REG_1),
+  html: (parse, match) => {
+    const [, , g2] = match;
+    return `<strong data-md="${BOLD_MD_1}">${parse(g2)}</strong>`;
+  },
+};
+
+const ITALIC_MD_1 = '*';
+const ITALIC_PREFIX_1 = `${ESC_NEG_LB}\\*`;
+const ITALIC_NEG_LA_1 = '(?!\\*)';
+const ITALIC_REG_1 = new RegExp(
+  `${URL_NEG_LB}${ITALIC_PREFIX_1}${MIN_ANY}${ITALIC_PREFIX_1}${ITALIC_NEG_LA_1}`
+);
+export const ItalicRule1: InlineMDRule = {
+  match: (text) => text.match(ITALIC_REG_1),
+  html: (parse, match) => {
+    const [, , g2] = match;
+    return `<i data-md="${ITALIC_MD_1}">${parse(g2)}</i>`;
+  },
+};
+
+const ITALIC_MD_2 = '_';
+const ITALIC_PREFIX_2 = `${ESC_NEG_LB}_`;
+const ITALIC_NEG_LA_2 = '(?!_)';
+const ITALIC_REG_2 = new RegExp(
+  `${URL_NEG_LB}${ITALIC_PREFIX_2}${MIN_ANY}${ITALIC_PREFIX_2}${ITALIC_NEG_LA_2}`
+);
+export const ItalicRule2: InlineMDRule = {
+  match: (text) => text.match(ITALIC_REG_2),
+  html: (parse, match) => {
+    const [, , g2] = match;
+    return `<i data-md="${ITALIC_MD_2}">${parse(g2)}</i>`;
+  },
+};
+
+const UNDERLINE_MD_1 = '__';
+const UNDERLINE_PREFIX_1 = `${ESC_NEG_LB}_{2}`;
+const UNDERLINE_NEG_LA_1 = '(?!_)';
+const UNDERLINE_REG_1 = new RegExp(
+  `${URL_NEG_LB}${UNDERLINE_PREFIX_1}${MIN_ANY}${UNDERLINE_PREFIX_1}${UNDERLINE_NEG_LA_1}`
+);
+export const UnderlineRule: InlineMDRule = {
+  match: (text) => text.match(UNDERLINE_REG_1),
+  html: (parse, match) => {
+    const [, , g2] = match;
+    return `<u data-md="${UNDERLINE_MD_1}">${parse(g2)}</u>`;
+  },
+};
+
+const STRIKE_MD_1 = '~~';
+const STRIKE_PREFIX_1 = `${ESC_NEG_LB}~{2}`;
+const STRIKE_NEG_LA_1 = '(?!~)';
+const STRIKE_REG_1 = new RegExp(
+  `${URL_NEG_LB}${STRIKE_PREFIX_1}${MIN_ANY}${STRIKE_PREFIX_1}${STRIKE_NEG_LA_1}`
+);
+export const StrikeRule: InlineMDRule = {
+  match: (text) => text.match(STRIKE_REG_1),
+  html: (parse, match) => {
+    const [, , g2] = match;
+    return `<s data-md="${STRIKE_MD_1}">${parse(g2)}</s>`;
+  },
+};
+
+const CODE_MD_1 = '`';
+const CODE_PREFIX_1 = `${ESC_NEG_LB}\``;
+const CODE_NEG_LA_1 = '(?!`)';
+const CODE_REG_1 = new RegExp(`${URL_NEG_LB}${CODE_PREFIX_1}(.+?)${CODE_PREFIX_1}${CODE_NEG_LA_1}`);
+export const CodeRule: InlineMDRule = {
+  match: (text) => text.match(CODE_REG_1),
+  html: (parse, match) => {
+    const [, , g2] = match;
+    return `<code data-md="${CODE_MD_1}">${g2}</code>`;
+  },
+};
+
+const SPOILER_MD_1 = '||';
+const SPOILER_PREFIX_1 = `${ESC_NEG_LB}\\|{2}`;
+const SPOILER_NEG_LA_1 = '(?!\\|)';
+const SPOILER_REG_1 = new RegExp(
+  `${URL_NEG_LB}${SPOILER_PREFIX_1}${MIN_ANY}${SPOILER_PREFIX_1}${SPOILER_NEG_LA_1}`
+);
+export const SpoilerRule: InlineMDRule = {
+  match: (text) => text.match(SPOILER_REG_1),
+  html: (parse, match) => {
+    const [, , g2] = match;
+    return `<span data-md="${SPOILER_MD_1}" data-mx-spoiler>${parse(g2)}</span>`;
+  },
+};
+
+const LINK_ALT = `\\[${MIN_ANY}\\]`;
+const LINK_URL = `\\((https?:\\/\\/.+?)\\)`;
+const LINK_REG_1 = new RegExp(`${LINK_ALT}${LINK_URL}`);
+export const LinkRule: InlineMDRule = {
+  match: (text) => text.match(LINK_REG_1),
+  html: (parse, match) => {
+    const [, g1, g2] = match;
+    return `<a data-md href="${g2}">${parse(g1)}</a>`;
+  },
+};
+
+export const INLINE_SEQUENCE_SET = '[*_~`|]';
+const ESC_SEQ_1 = `\\\\(${INLINE_SEQUENCE_SET})`;
+const ESC_REG_1 = new RegExp(`${URL_NEG_LB}${ESC_SEQ_1}`);
+export const EscapeRule: InlineMDRule = {
+  match: (text) => text.match(ESC_REG_1),
+  html: (parse, match) => {
+    const [, , g2] = match;
+    return g2;
+  },
+};
@@ -0,0 +1,62 @@
+import { MatchResult, replaceMatch } from '../internal';
+import { InlineMDParser, InlineMDRule } from './type';
+
+/**
+ * Runs a single markdown rule on the provided text.
+ *
+ * @param text - The text to parse.
+ * @param rule - The markdown rule to run.
+ * @param parse - A function that run the parser on remaining parts.
+ * @returns The text with the markdown rule applied or `undefined` if no match is found.
+ */
+export const runInlineRule = (
+  text: string,
+  rule: InlineMDRule,
+  parse: InlineMDParser
+): string | undefined => {
+  const matchResult = rule.match(text);
+  if (matchResult) {
+    const content = rule.html(parse, matchResult);
+    return replaceMatch(text, matchResult, content, (txt) => [parse(txt)]).join('');
+  }
+  return undefined;
+};
+
+/**
+ * Runs multiple rules at the same time to better handle nested rules.
+ * Rules will be run in the order they appear.
+ *
+ * @param text - The text to parse.
+ * @param rules - The markdown rules to run.
+ * @param parse - A function that run the parser on remaining parts.
+ * @returns The text with the markdown rules applied or `undefined` if no match is found.
+ */
+export const runInlineRules = (
+  text: string,
+  rules: InlineMDRule[],
+  parse: InlineMDParser
+): string | undefined => {
+  const matchResults = rules.map((rule) => rule.match(text));
+
+  let targetRule: InlineMDRule | undefined;
+  let targetResult: MatchResult | undefined;
+
+  for (let i = 0; i < matchResults.length; i += 1) {
+    const currentResult = matchResults[i];
+    if (currentResult && typeof currentResult.index === 'number') {
+      if (
+        !targetResult ||
+        (typeof targetResult?.index === 'number' && currentResult.index < targetResult.index)
+      ) {
+        targetResult = currentResult;
+        targetRule = rules[i];
+      }
+    }
+  }
+
+  if (targetRule && targetResult) {
+    const content = targetRule.html(parse, targetResult);
+    return replaceMatch(text, targetResult, content, (txt) => [parse(txt)]).join('');
+  }
+  return undefined;
+};
@@ -0,0 +1,26 @@
+import { MatchResult, MatchRule } from '../internal';
+
+/**
+ * Type for a function that parses inline markdown into HTML.
+ *
+ * @param text - The markdown text to be parsed.
+ * @returns The parsed HTML.
+ */
+export type InlineMDParser = (text: string) => string;
+
+/**
+ * Type for a function that converts a match to output.
+ *
+ * @param parse - The inline markdown parser function.
+ * @param match - The match result.
+ * @returns The output string after processing the match.
+ */
+export type InlineMatchConverter = (parse: InlineMDParser, match: MatchResult) => string;
+
+/**
+ * Type representing a markdown rule that includes a matching pattern and HTML conversion.
+ */
+export type InlineMDRule = {
+  match: MatchRule; // A function that matches a specific markdown pattern.
+  html: InlineMatchConverter; // A function that converts the match to HTML.
+};