introducing a possibility to ignore values in escape and escapeId

Author: SeregPie

lib/SqlString.js

@@ -23,6 +23,10 @@ SqlString.escapeId = function escapeId(val, forbidQualified) {
     return sql;
   }
 
+  if (val instanceof Escaped) {
+    return String(val);
+  }
+
   if (forbidQualified) {
     return '`' + String(val).replace(/`/g, '``') + '`';
   }
@@ -39,7 +43,9 @@ SqlString.escape = function escape(val, stringifyObjects, timeZone) {
     case 'boolean': return (val) ? 'true' : 'false';
     case 'number': return val + '';
     case 'object':
-      if (val instanceof Date) {
+      if (val instanceof Escaped) {
+        return String(val);
+      } else if (val instanceof Date) {
         return SqlString.dateToString(val, timeZone || 'local');
       } else if (Array.isArray(val)) {
         return SqlString.arrayToList(val, timeZone);
@@ -54,6 +60,10 @@ SqlString.escape = function escape(val, stringifyObjects, timeZone) {
   }
 };
 
+SqlString.escaped = function escaped(val) {
+  return new Escaped(val);
+};
+
 SqlString.arrayToList = function arrayToList(array, timeZone) {
   var sql = '';
 
@@ -216,3 +226,9 @@ function convertTimezone(tz) {
   }
   return false;
 }
+
+function Escaped(val) {
+  this.toString = function toString() {
+    return String(val);
+  };
+}

test/unit/test-SqlString.js

@@ -33,6 +33,10 @@ test('SqlString.escapeId', {
 
   'nested arrays are flattened': function() {
     assert.equal(SqlString.escapeId(['a', ['b', ['t.c']]]), "`a`, `b`, `t`.`c`");
+  },
+
+  'instances of Escaped are not quoted': function() {
+    assert.equal(SqlString.escapeId(SqlString.escaped('@a := 42')), "@a := 42");
   }
 });
 
@@ -82,6 +86,10 @@ test('SqlString.escape', {
     assert.equal(SqlString.escape('Super'), "'Super'");
   },
 
+  'instances of Escaped get not escaped': function() {
+    assert.equal(SqlString.escape({a: SqlString.escaped('@a')}), "`a` = @a");
+  },
+
   '\0 gets escaped': function() {
     assert.equal(SqlString.escape('Sup\0er'), "'Sup\\0er'");
     assert.equal(SqlString.escape('Super\0'), "'Super\\0'");