chore: adds better error logging for detect features

detectFeatures.js

@@ -68,10 +68,14 @@ const detectFeatures = (code, ecmaVersion, sourceType) => {
    * @note Fail if any unsupported features were used.
    */
   if (unsupportedFeatures.length > 0) {
-    throw new Error(
+    const error = new Error(
       `Unsupported features detected: ${unsupportedFeatures.join(', ')}. ` +
       `These require a higher ES version than ${ecmaVersion}.`
     );
+    error.type = 'ES-Check';
+    error.features = unsupportedFeatures;
+    error.ecmaVersion = ecmaVersion;
+    throw error;
   }
 
   return {

index.js

@@ -10,6 +10,7 @@ const path = require('path')
 const supportsColor = require('supports-color')
 const winston = require('winston')
 const detectFeatures = require('./detectFeatures')
+const { formatError } = require('./utils')
 const pkg = require('./package.json')
 
 /**
@@ -226,13 +227,11 @@ program
       logger.debug(`Features found in ${file}: ${stringifiedFeatures}`);
       const isSupported = unsupportedFeatures.length === 0;
       if (!isSupported) {
-        logger.error(
-          `ES-Check: The file "${file}" uses these unsupported features: ${unsupportedFeatures.join(', ')}
-          but your target is ES${ecmaVersion}.`
-        );
+        const error = new Error(`Unsupported features used: ${unsupportedFeatures.join(', ')} but your target is ES${ecmaVersion}.`);
         errArray.push({
-          err: new Error(`Unsupported features used: ${unsupportedFeatures.join(', ')}`),
+          err: error,
           file,
+          stack: error.stack
         });
       }
     })

utils.js

@@ -158,10 +158,25 @@ const checkMap = {
   default: () => false,
 };
 
+const formatError = (filePath, error) => {
+  console.error('error: ES-Check: there were 1 ES version matching errors.');
+  console.info(`
+          ES-Check Error:
+          ----
+          · erroring file: ${filePath}
+          · error: ${error.message}
+          · see the printed err.stack below for context
+          ----
+          
+          ${error.stack}
+  `);
+};
+
 module.exports = {
   checkVarKindMatch,
   checkCalleeMatch,
   checkOperatorMatch,
   checkDefault,
   checkMap,
+  formatError,
 };