Add parsers parameter to readConfig/Sync to support non-JSON formats like YAML (fixes #118).

lib/markdownlint.js

@@ -422,6 +422,7 @@ function lintFile(
   }
 }
 
+// Lints files and strings
 function lintInput(options, synchronous, callback) {
   // Normalize inputs
   options = options || {};
@@ -517,34 +518,64 @@ function markdownlintSync(options) {
   return results;
 }
 
+// Parses the content of a configuration file
+function parseConfiguration(name, content, parsers) {
+  let config = null;
+  let message = "";
+  const errors = [];
+  // Try each parser
+  (parsers || [ JSON.parse ]).every((parser) => {
+    try {
+      config = parser(content);
+    } catch (ex) {
+      errors.push(ex.message);
+    }
+    return !config;
+  });
+  // Message if unable to parse
+  if (!config) {
+    errors.unshift(`Unable to parse '${name}'`);
+    message = errors.join("; ");
+  }
+  return {
+    config,
+    message
+  };
+}
+
 /**
  * Read specified configuration file.
  *
  * @param {String} file Configuration file name/path.
+ * @param {Array} [parsers] Optional parsing function(s).
  * @param {Function} callback Callback (err, result) function.
  * @returns {void}
  */
-function readConfig(file, callback) {
+function readConfig(file, parsers, callback) {
+  if (!callback) {
+    // @ts-ignore
+    callback = parsers;
+    parsers = null;
+  }
   // Read file
-  fs.readFile(file, shared.utf8Encoding, function handleFile(err, content) {
+  fs.readFile(file, shared.utf8Encoding, (err, content) => {
     if (err) {
       return callback(err);
     }
-    // Parse file
-    let config = null;
-    try {
-      config = JSON.parse(content);
-    } catch (ex) {
-      return callback(ex);
+    // Try to parse file
+    const { config, message } = parseConfiguration(file, content, parsers);
+    if (!config) {
+      return callback(new Error(message));
     }
-    if (config.extends) {
-      // Extend configuration
-      const extendsFile = path.resolve(path.dirname(file), config.extends);
-      readConfig(extendsFile, function handleConfig(errr, extendsConfig) {
+    // Extend configuration
+    const configExtends = config.extends;
+    if (configExtends) {
+      delete config.extends;
+      const extendsFile = path.resolve(path.dirname(file), configExtends);
+      readConfig(extendsFile, parsers, (errr, extendsConfig) => {
         if (errr) {
           return callback(errr);
         }
-        delete config.extends;
         callback(null, shared.assign(extendsConfig, config));
       });
     } else {
@@ -557,17 +588,24 @@ function readConfig(file, callback) {
  * Read specified configuration file synchronously.
  *
  * @param {String} file Configuration file name/path.
+ * @param {Array} [parsers] Optional parsing function(s).
  * @returns {Object} Configuration object.
  */
-function readConfigSync(file) {
-  // Parse file
-  let config = JSON.parse(fs.readFileSync(file, shared.utf8Encoding));
-  if (config.extends) {
-    // Extend configuration
-    config = shared.assign(
-      readConfigSync(path.resolve(path.dirname(file), config.extends)),
-      config);
+function readConfigSync(file, parsers) {
+  // Read file
+  const content = fs.readFileSync(file, shared.utf8Encoding);
+  // Try to parse file
+  const { config, message } = parseConfiguration(file, content, parsers);
+  if (!config) {
+    throw new Error(message);
+  }
+  // Extend configuration
+  const configExtends = config.extends;
+  if (configExtends) {
     delete config.extends;
+    return shared.assign(
+      readConfigSync(path.resolve(path.dirname(file), configExtends), parsers),
+      config);
   }
   return config;
 }