1 files changed, 55 insertions, 0 deletions
diff --git a/app/assets/javascripts/ide/lib/editorconfig/parser.js b/app/assets/javascripts/ide/lib/editorconfig/parser.js
new file mode 100644
index 00000000000..a30a8cb868d
--- /dev/null
+++ b/app/assets/javascripts/ide/lib/editorconfig/parser.js
@@ -0,0 +1,55 @@
+import { parseString } from 'editorconfig/src/lib/ini';
+import minimatch from 'minimatch';
+import { getPathParents } from '../../utils';
+
+const dirname = path => path.replace(/\.editorconfig$/, '');
+
+function isRootConfig(config) {
+  return config.some(([pattern, rules]) => !pattern && rules?.root === 'true');
+}
+
+function getRulesForSection(path, [pattern, rules]) {
+  if (!pattern) {
+    return {};
+  }
+  if (minimatch(path, pattern, { matchBase: true })) {
+    return rules;
+  }
+
+  return {};
+}
+
+function getRulesWithConfigs(filePath, configFiles = [], rules = {}) {
+  if (!configFiles.length) return rules;
+
+  const [{ content, path: configPath }, ...nextConfigs] = configFiles;
+  const configDir = dirname(configPath);
+
+  if (!filePath.startsWith(configDir)) return rules;
+
+  const parsed = parseString(content);
+  const isRoot = isRootConfig(parsed);
+  const relativeFilePath = filePath.slice(configDir.length);
+
+  const sectionRules = parsed.reduce(
+    (acc, section) => Object.assign(acc, getRulesForSection(relativeFilePath, section)),
+    {},
+  );
+
+  // prefer existing rules by overwriting to section rules
+  const result = Object.assign(sectionRules, rules);
+
+  return isRoot ? result : getRulesWithConfigs(filePath, nextConfigs, result);
+}
+
+// eslint-disable-next-line import/prefer-default-export
+export function getRulesWithTraversal(filePath, getFileContent) {
+  const editorconfigPaths = [
+    ...getPathParents(filePath).map(x => `${x}/.editorconfig`),
+    '.editorconfig',
+  ];
+
+  return Promise.all(
+    editorconfigPaths.map(path => getFileContent(path).then(content => ({ path, content }))),
+  ).then(results => getRulesWithConfigs(filePath, results.filter(x => x.content)));
+}