extend keep_quoted_props over numeric keys (#5094)

fixes #5093

Author: alexlamsl

lib/output.js

@@ -1690,28 +1690,21 @@ function OutputStream(options) {
 
     function print_property_key(self, output) {
         var key = self.key;
-        if (key instanceof AST_Node) {
-            output.with_square(function() {
-                key.print(output);
-            });
-        } else if (output.option("quote_keys")) {
-            output.print_string(key);
+        if (key instanceof AST_Node) return output.with_square(function() {
+            key.print(output);
+        });
+        var quote = self.start && self.start.quote;
+        if (output.option("quote_keys") || quote && output.option("keep_quoted_props")) {
+            output.print_string(key, quote);
         } else if ("" + +key == key && key >= 0) {
             output.print(make_num(key));
+        } else if (self.private) {
+            output.print_name(key);
+        } else if (RESERVED_WORDS[key] ? !output.option("ie") : is_identifier_string(key)) {
+            output.print_name(key);
+            return key;
         } else {
-            var quote = self.start && self.start.quote;
-            if (self.private) {
-                output.print_name(key);
-            } else if (RESERVED_WORDS[key] ? !output.option("ie") : is_identifier_string(key)) {
-                if (quote && output.option("keep_quoted_props")) {
-                    output.print_string(key, quote);
-                } else {
-                    output.print_name(key);
-                    return key;
-                }
-            } else {
-                output.print_string(key, quote);
-            }
+            output.print_string(key, quote);
         }
     }
     DEFPRINT(AST_ObjectKeyVal, function(output) {

test/compress/properties.js

@@ -1463,3 +1463,50 @@ issue_4888: {
     }
     expect_stdout: "object"
 }
+
+issue_5093: {
+    beautify = {
+        keep_quoted_props: true,
+    }
+    input: {
+        console.log({
+            a: true,
+            '42': "PASS",
+            "null": [],
+        }[6 * 7]);
+    }
+    expect_exact: 'console.log({a:true,"42":"PASS","null":[]}[6*7]);'
+    expect_stdout: "PASS"
+}
+
+issue_5093_quote_keys: {
+    beautify = {
+        keep_quoted_props: true,
+        quote_keys: true,
+    }
+    input: {
+        console.log({
+            a: true,
+            '42': "PASS",
+            "null": [],
+        }[6 * 7]);
+    }
+    expect_exact: 'console.log({"a":true,"42":"PASS","null":[]}[6*7]);'
+    expect_stdout: "PASS"
+}
+
+issue_5093_quote_style: {
+    beautify = {
+        keep_quoted_props: true,
+        quote_style: 3,
+    }
+    input: {
+        console.log({
+            a: true,
+            '42': "PASS",
+            "null": [],
+        }[6 * 7]);
+    }
+    expect_exact: 'console.log({a:true,\'42\':"PASS","null":[]}[6*7]);'
+    expect_stdout: "PASS"
+}