feat(ts-estree): fix parsing nested sequence expressions (typescript-eslint#286)

Author: armano2

Diff for: packages/parser/tests/lib/__snapshots__/javascript.ts.snap

@@ -0,0 +1 @@
+var xx = (xx ? x++ : 4, 10);

Diff for: packages/shared-fixtures/fixtures/javascript/commaOperator/comma-operator-conditional.src.js

@@ -0,0 +1 @@
+var v1 = (1, 2, 3, 4, 5, 6, 7);

Diff for: packages/shared-fixtures/fixtures/javascript/commaOperator/comma-operator-multi.src.js

@@ -0,0 +1 @@
+var v1 = ((1, 2, 3), 4, 5, (6, 7));

Diff for: packages/shared-fixtures/fixtures/javascript/commaOperator/comma-operator-nested.src.js

@@ -0,0 +1,4 @@
+function f1() {
+  var a = 1;
+  return a, v1, a;
+}

Diff for: packages/shared-fixtures/fixtures/javascript/commaOperator/comma-operator-return.src.js

@@ -0,0 +1 @@
+const foo = (((1, 2)));

Diff for: packages/shared-fixtures/fixtures/javascript/commaOperator/comma-operator-simple-nested.src.js

@@ -0,0 +1 @@
+const foo = (1);

Diff for: packages/shared-fixtures/fixtures/javascript/commaOperator/comma-operator-simple.src.js

@@ -1596,20 +1596,17 @@ export class Converter {
             expressions: []
           });
 
-          const left = this.convertChild(node.left),
-            right = this.convertChild(node.right);
-
-          if (left.type === AST_NODE_TYPES.SequenceExpression) {
+          const left = this.convertChild(node.left);
+          if (
+            left.type === AST_NODE_TYPES.SequenceExpression &&
+            node.left.kind !== SyntaxKind.ParenthesizedExpression
+          ) {
             result.expressions = result.expressions.concat(left.expressions);
           } else {
             result.expressions.push(left);
           }
 
-          if (right.type === AST_NODE_TYPES.SequenceExpression) {
-            result.expressions = result.expressions.concat(right.expressions);
-          } else {
-            result.expressions.push(right);
-          }
+          result.expressions.push(this.convertChild(node.right));
           return result;
         } else {
           const type = getBinaryExpressionType(node.operatorToken);

Diff for: packages/typescript-estree/src/convert.ts

@@ -206,6 +206,8 @@ tester.addFixturePatternConfig('javascript/classes', {
   ]
 });
 
+tester.addFixturePatternConfig('javascript/commaOperator');
+
 tester.addFixturePatternConfig('javascript/defaultParams');
 
 tester.addFixturePatternConfig('javascript/destructuring');