From 4c335cae0afd862e7d143b1cf8bd08f9ab8f932a Mon Sep 17 00:00:00 2001
From: Brian Ng <bng412@gmail.com>
Date: Mon, 31 Jul 2017 15:40:14 -0500
Subject: [PATCH] Add support for printing optional catch binding (#2570)

---
 src/parser-babylon.js                         |  3 ++-
 src/printer.js                                |  5 ++---
 .../__snapshots__/jsfmt.spec.js.snap          | 19 +++++++++++++++++++
 tests/optional_catch_binding/jsfmt.spec.js    |  1 +
 .../optional_catch_binding.js                 |  9 +++++++++
 5 files changed, 33 insertions(+), 4 deletions(-)
 create mode 100644 tests/optional_catch_binding/__snapshots__/jsfmt.spec.js.snap
 create mode 100644 tests/optional_catch_binding/jsfmt.spec.js
 create mode 100644 tests/optional_catch_binding/optional_catch_binding.js

diff --git a/src/parser-babylon.js b/src/parser-babylon.js
index 0adb9f65..72910136 100644
--- a/src/parser-babylon.js
+++ b/src/parser-babylon.js
@@ -23,7 +23,8 @@ function parse(text, parsers, opts) {
       "functionSent",
       "dynamicImport",
       "numericSeparator",
-      "importMeta"
+      "importMeta",
+      "optionalCatchBinding"
     ]
   };
 
diff --git a/src/printer.js b/src/printer.js
index 1782cc2a..840fbe02 100644
--- a/src/printer.js
+++ b/src/printer.js
@@ -1552,9 +1552,8 @@ function genericPrintNoParens(path, options, print, args) {
       ]);
     case "CatchClause":
       return concat([
-        "catch (",
-        path.call(print, "param"),
-        ") ",
+        "catch ",
+        n.param ? concat(["(", path.call(print, "param"), ") "]) : "",
         path.call(print, "body")
       ]);
     case "ThrowStatement":
diff --git a/tests/optional_catch_binding/__snapshots__/jsfmt.spec.js.snap b/tests/optional_catch_binding/__snapshots__/jsfmt.spec.js.snap
new file mode 100644
index 00000000..7253c29b
--- /dev/null
+++ b/tests/optional_catch_binding/__snapshots__/jsfmt.spec.js.snap
@@ -0,0 +1,19 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`optional_catch_binding.js 1`] = `
+try {
+
+}
+catch {
+
+}
+finally {
+
+}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+try {
+} catch {
+} finally {
+}
+
+`;
diff --git a/tests/optional_catch_binding/jsfmt.spec.js b/tests/optional_catch_binding/jsfmt.spec.js
new file mode 100644
index 00000000..f974ed6c
--- /dev/null
+++ b/tests/optional_catch_binding/jsfmt.spec.js
@@ -0,0 +1 @@
+run_spec(__dirname, { parser: "babylon" });
diff --git a/tests/optional_catch_binding/optional_catch_binding.js b/tests/optional_catch_binding/optional_catch_binding.js
new file mode 100644
index 00000000..09fbc459
--- /dev/null
+++ b/tests/optional_catch_binding/optional_catch_binding.js
@@ -0,0 +1,9 @@
+try {
+
+}
+catch {
+
+}
+finally {
+
+}