Initial implementation of markdownlint-micromark package, micromark.mjs helpers, and tests.

lib/micromark.mjs

@@ -0,0 +1,78 @@
+import assert from "node:assert/strict";
+// eslint-disable-next-line n/no-unpublished-import
+import { parse, postprocess, preprocess } from "../micromark/exports.mjs";
+
+/**
+ * Markdown token.
+ *
+ * @typedef {Object} Token
+ * @property {string} type Token type.
+ * @property {number} startLine Start line (1-based).
+ * @property {number} startColumn Start column (1-based).
+ * @property {number} endLine End line (1-based).
+ * @property {number} endColumn End column (1-based).
+ * @property {string} text Token text.
+ * @property {Token[]} tokens Child tokens.
+ */
+
+/**
+ * Parses a Markdown document and returns tokens.
+ *
+ * @param {string} markdown Markdown document.
+ * @returns {Token[]} Markdown tokens.
+ */
+function micromarkParse(markdown) {
+
+  // Use micromark to parse document into Events
+  const encoding = undefined;
+  const eol = true;
+  const options = undefined;
+  const chunks = preprocess()(markdown, encoding, eol);
+  const parseContext = parse(options).document().write(chunks);
+  const events = postprocess(parseContext);
+
+  // Create Token objects
+  const document = [];
+  let current = {
+    "tokens": document
+  };
+  const history = [ current ];
+  for (const event of events) {
+    const [ kind, token, context ] = event;
+    const { type, start, end, _container } = token;
+    const { "column": startColumn, "line": startLine } = start;
+    const { "column": endColumn, "line": endLine } = end;
+    // sliceSerialize throws when called for a _container
+    const text = _container ? null : context.sliceSerialize(token);
+    if (kind === "enter") {
+      const previous = current;
+      history.push(previous);
+      current = {
+        type,
+        startLine,
+        startColumn,
+        endLine,
+        endColumn,
+        text,
+        "tokens": []
+      };
+      previous.tokens.push(current);
+    } else if (kind === "exit") {
+      assert.equal(type, current.type);
+      assert.equal(startLine, current.startLine);
+      assert.equal(startColumn, current.startColumn);
+      assert.equal(endLine, current.endLine);
+      assert.equal(endColumn, current.endColumn);
+      assert.equal(text, current.text);
+      current = history.pop();
+      assert.ok(current, "Empty history");
+    }
+  }
+
+  // Return document
+  return document;
+}
+
+export {
+  micromarkParse as parse
+};