chore: import upstream snapshot with attribution

tools/challenge-parser/parser/plugins/utils/get-file-visitor.js

@@ -0,0 +1,99 @@
+const { isEmpty } = require('lodash');
+const is = require('unist-util-is');
+const position = require('unist-util-position');
+
+const getId = require('./get-id');
+
+const supportedLanguages = [
+  'js',
+  'css',
+  'html',
+  'jsx',
+  'py',
+  'ts',
+  'tsx',
+  'json'
+];
+const longToShortLanguages = {
+  javascript: 'js',
+  typescript: 'ts',
+  python: 'py'
+};
+
+function defaultFile(lang, id) {
+  return {
+    ext: lang,
+    name: getFilenames(lang),
+    contents: '',
+    id
+  };
+}
+
+function getFilenames(lang) {
+  const langToFilename = {
+    js: 'script',
+    css: 'styles',
+    py: 'main',
+    json: 'tsconfig'
+  };
+  return langToFilename[lang] ?? 'index';
+}
+
+function getFileVisitor(seeds, seedKey, validate) {
+  return (node, index, parent) => {
+    if (is(node, 'root')) return;
+    if (is(node, 'code')) {
+      codeToData(node, seeds, seedKey, validate);
+      return;
+    }
+    idToData(node, index, parent, seeds);
+  };
+}
+
+function codeToData(node, seeds, seedKey, validate) {
+  if (validate) validate(node);
+  const lang = node.lang;
+  const shortLang = longToShortLanguages[lang] ?? lang;
+  if (!supportedLanguages.includes(shortLang))
+    throw Error(`On line ${
+      position.start(node).line
+    } '${shortLang}' is not a supported language.
+ Please use one of js, css, html, jsx, ts, tsx or py
+`);
+
+  const fileId = `index${shortLang}`;
+  const id = seeds[fileId] ? seeds[fileId].id : '';
+  // the contents will be missing if there is an id preceding this code
+  // block.
+  if (!seeds[fileId]) {
+    seeds[fileId] = defaultFile(shortLang, id);
+  }
+  seeds[fileId][seedKey] = isEmpty(seeds[fileId][seedKey])
+    ? node.value
+    : seeds[fileId][seedKey] + '\n' + node.value;
+}
+
+function idToData(node, index, parent, seeds) {
+  const id = getId(node);
+
+  // If this is reached, the node type is neither root nor code. If it is not
+  // an id, there must be a syntax error.
+  if (!id) {
+    throw Error(
+      'Unexpected syntax in seed/solution. Must be ::id{#id} or a code ' +
+        'block (```) \n'
+    );
+  }
+  const codeNode = parent.children[index + 1];
+  if (codeNode && is(codeNode, 'code')) {
+    const shortLang = longToShortLanguages[codeNode.lang] ?? codeNode.lang;
+    const fileKey = `index${shortLang}`;
+    if (seeds[fileKey]) throw Error('::id{#id}s must come before code blocks');
+    seeds[fileKey] = defaultFile(shortLang, id);
+  } else {
+    throw Error('::id{#id}s must come before code blocks');
+  }
+}
+
+module.exports.getFileVisitor = getFileVisitor;
+module.exports.getFilenames = getFilenames;