Make all the member expressions but the last one part of the first group (#589)

Fixes #587

src/printer.js

@@ -2106,7 +2106,11 @@ function printMemberChain(path, options, print) {
   //     .d()
   //     .e
 
-  // The first group is the first node followed by as many CallExpression as possible
+  // The first group is the first node followed by
+  //   - as many CallExpression as possible
+  //       < fn()()() >.something()
+  //   - then, as many MemberExpression as possible but the last one
+  //       < this.items >.something()
   var groups = [];
   var currentGroup = [printedNodes[0]];
   var i = 1;
@@ -2117,6 +2121,14 @@ function printMemberChain(path, options, print) {
       break;
     }
   }
+  for (; i + 1 < printedNodes.length; ++i) {
+    if (printedNodes[i].node.type === "MemberExpression" &&
+        printedNodes[i + 1].node.type === "MemberExpression") {
+      currentGroup.push(printedNodes[i]);
+    } else {
+      break;
+    }
+  }
   groups.push(currentGroup);
   currentGroup = [];
 

tests/method-chain/__snapshots__/jsfmt.spec.js.snap

@@ -166,3 +166,14 @@ method().then(x => x)[\"abc\"](x => x)[abc](x => x);
 ({}).a().b();
 "
 `;
+
+exports[`test this.js 1`] = `
+"const sel = this.connections
+  .concat(this.activities.concat(this.operators))
+  .filter(x => x.selected);
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+const sel = this.connections
+  .concat(this.activities.concat(this.operators))
+  .filter(x => x.selected);
+"
+`;

tests/method-chain/this.js

@@ -0,0 +1,3 @@
+const sel = this.connections
+  .concat(this.activities.concat(this.operators))
+  .filter(x => x.selected);