fix: don't redefined sqlstring.escape (#39)

Author: dead-horse

lib/sqlstring.js

@@ -9,11 +9,13 @@ const Literal = require('./literals').Literal;
 
 module.exports = SqlString;
 
-SqlString.__escape = SqlString.escape;
+if (!SqlString.__escape) {
+  SqlString.__escape = SqlString.escape;
 
-SqlString.escape = function(val, stringifyObjects, timeZone) {
-  if (val instanceof Literal) {
-    return val.toString();
-  }
-  return SqlString.__escape(val, stringifyObjects, timeZone);
-};
+  SqlString.escape = function(val, stringifyObjects, timeZone) {
+    if (val instanceof Literal) {
+      return val.toString();
+    }
+    return SqlString.__escape(val, stringifyObjects, timeZone);
+  };
+}

test/sqlstring.test.js

@@ -17,5 +17,14 @@ describe('sqlstring.test.js', function() {
       assert.equal(SqlString.escape(literals.Literal('sum2()')), 'sum2()');
       assert.equal(SqlString.escape(literals.now), mysql.escape(literals.now));
     });
+
+    it('should only patch once', function() {
+      require.cache[require.resolve('../lib/sqlstring')] = null;
+      const AnotherSqlString = require('../lib/sqlstring');
+      assert.equal(AnotherSqlString.escape(literals.now), 'now()');
+      assert.equal(AnotherSqlString.escape(new literals.Literal('sum')), 'sum');
+      assert.equal(AnotherSqlString.escape(literals.Literal('sum2()')), 'sum2()');
+      assert.equal(AnotherSqlString.escape(literals.now), mysql.escape(literals.now));
+    });
   });
 });