From afca3d7e7adc0fb30da048ad4ffcf058c831311a Mon Sep 17 00:00:00 2001
From: Christopher Chedeau <vjeux@fb.com>
Date: Wed, 11 Jan 2017 20:36:47 -0800
Subject: [PATCH] Minimize string escapes

If there you are opting in for double quote but there's a string with a double quote in it, it's better to swap to a single quote to avoid having too many `\`. Note that if there are both single and double quotes in the string, we should use the default string instead.

Fixes #139
---
 src/printer.js                                      | 13 ++++++++++++-
 .../child_process/__snapshots__/jsfmt.spec.js.snap  |  4 +---
 tests/strings/__snapshots__/jsfmt.spec.js.snap      |  6 +++---
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/printer.js b/src/printer.js
index 78d2d64d..1edaebaa 100644
--- a/src/printer.js
+++ b/src/printer.js
@@ -2059,7 +2059,18 @@ function swapQuotes(str) {
 function nodeStr(str, options) {
   isString.assert(str);
 
-  if (options.singleQuote) {
+  const containsSingleQuote = str.indexOf("'") !== -1;
+  const containsDoubleQuote = str.indexOf('"') !== -1;
+
+  let shouldUseSingleQuote = options.singleQuote;
+  if (options.singleQuote && containsSingleQuote && !containsDoubleQuote) {
+    shouldUseSingleQuote = false;
+  }
+  if (!options.singleQuote && !containsSingleQuote && containsDoubleQuote) {
+    shouldUseSingleQuote = true;
+  }
+
+  if (shouldUseSingleQuote) {
     return swapQuotes(JSON.stringify(swapQuotes(str)));
   } else {
     return JSON.stringify(str);
diff --git a/tests/node_tests/child_process/__snapshots__/jsfmt.spec.js.snap b/tests/node_tests/child_process/__snapshots__/jsfmt.spec.js.snap
index 2b00c505..630144e9 100644
--- a/tests/node_tests/child_process/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/node_tests/child_process/__snapshots__/jsfmt.spec.js.snap
@@ -164,9 +164,7 @@ var ls = child_process.spawn(\"ls\");
 var wc = child_process.spawn(\"wc\", [ \"-l\" ]);
 
 // args + options.
-child_process.spawn(\"echo\", [ \"-n\", \"\\\"Testing...\\\"\" ], {
-  env: { TEST: \"foo\" }
-});
+child_process.spawn(\"echo\", [ \"-n\", \'\"Testing...\"\' ], { env: { TEST: \"foo\" } });
 
 // options only.
 child_process.spawn(\"echo\", { env: { FOO: 2 } });
diff --git a/tests/strings/__snapshots__/jsfmt.spec.js.snap b/tests/strings/__snapshots__/jsfmt.spec.js.snap
index 288c13f8..2edc67b5 100644
--- a/tests/strings/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/strings/__snapshots__/jsfmt.spec.js.snap
@@ -26,9 +26,9 @@ exports[`test strings.js 1`] = `
 
 \"\'\";
 
-\"\\\"\";
-\"\\\"\";
-\"\\\\\\\"\";
+\'\"\';
+\'\"\';
+\'\\\\\"\';
 
 \"\'\";
 \"\'\";