fix: add error for not closed parenthesis in parse-parenthesis-content

Author: marcalexiei

src/constant.js

@@ -1 +1,3 @@
 export const METHOD = 'map-get((';
+
+export const ERROR_PREFIX = 'postcss – map-get';

src/parse-parenthesis-content.js

@@ -1,7 +1,9 @@
+import {ERROR_PREFIX} from './constant';
+
 /**
  * Get all the content inside brackets
- * @param {string} stringToParse string with parenthesis. This string must start with an `()`
- * @param {string} [startingPosition] to start parsing
+ * @param {string} stringToParse string with parenthesis. This string must start with an `(`
+ * @param {number} [startingPosition] to start parsing
  * @returns {{content: string, position: number}} All the content inside parenthesis including nested properties
  *
  * @todo might worth to parse the string until a `(` is found?
@@ -11,10 +13,10 @@ export default function parseParenthesisContent(stringToParse, startingPosition
   let content = '';
 
   const stack = [];
-  while (true) { // eslint-disable-line no-constant-condition
+  while (position !== stringToParse.length) {
     const mapChracter = stringToParse[position];
     if (mapChracter === '(') {
-      stack.push(mapChracter);
+      stack.push(position);
     } else if (mapChracter === ')') {
       stack.pop();
     }
@@ -27,5 +29,12 @@ export default function parseParenthesisContent(stringToParse, startingPosition
     }
   }
 
+  /**
+   * String should be already validated by postcss but to avoid unclear stacktrace I'll manage the error anyway.
+   */
+  if (stack.length !== 0) {
+    throw new Error(`${ERROR_PREFIX} – parenthesis not closed`);
+  }
+
   return {content, position};
 }

test/test.parse-parenthesis-content.js

@@ -31,3 +31,14 @@ tests.forEach(({stringToParse, startPosition, expectedContent}, testIndex) => {
     t.deepEqual(output.position, expectedPosition);
   });
 });
+
+test('it should throw an error when number of parenthesis is not exact', t => {
+  // missing parenthesis position:                     ↓
+  const value = '(map-get((corporate: (textColor: green, ea: (textColor: black), corporate), textColor)';
+
+  const testError = t.throws(() => {
+    parseParenthesisContent(value);
+  }, null);
+
+  t.is(testError.message, 'postcss – map-get – parenthesis not closed');
+});