Don't break support for NAPI_VERSION < 6

Author: renatoalencar

package.json

@@ -14,6 +14,7 @@
     "remote_path": "v{version}",
     "package_name": "napi-v{napi_build_version}-{platform}-{libc}-{arch}.tar.gz",
     "napi_versions": [
+      3,
       6
     ]
   },

src/statement.cc

@@ -204,6 +204,7 @@ template <class T> Values::Field*
     else if (OtherInstanceOf(source.As<Object>(), "Date")) {
         return new Values::Float(pos, source.ToNumber().DoubleValue());
     }
+#if NAPI_VERSION >= 6
     else if (source.IsBigInt()) {
         bool lossless;
         auto ret = new Values::Integer(pos, source.As<Napi::BigInt>().Int64Value(&lossless));
@@ -218,6 +219,7 @@ template <class T> Values::Field*
 
         return ret;
     }
+#endif
     else if (source.IsObject()) {
         Napi::String napiVal = source.ToString();
         // Check whether toString returned a value that is not undefined.
@@ -826,11 +828,13 @@ Napi::Value Statement::RowToJS(Napi::Env env, Row* row) {
             case SQLITE_INTEGER: {
                 auto field_value = ((Values::Integer*)field)->value;
 
+#if NAPI_VERSION >= 6
                 if (field_value > JS_MAX_SAFE_INTEGER || field_value < JS_MIN_SAFE_INTEGER) {
                     value = Napi::BigInt::New(env, field_value);
-                }
-                else {
-                    value = Napi::Number::New(env, ((Values::Integer*)field)->value);
+                } else
+#endif
+                {
+                    value = Napi::Number::New(env, field_value);
                 }
             } break;
             case SQLITE_FLOAT: {

test/other_objects.test.js

@@ -96,23 +96,25 @@ describe('data types', function() {
         });
     });
 
-    [
-        1n,
-        1337n,
-        8876343627091516928n,
-        -8876343627091516928n,
-    ].forEach(function (bigint) {
-        it('should serialize BigInt ' + bigint, function (done) {
-            db.run("INSERT INTO bigint_table VALUES(?)", bigint, function(err) {
-                if (err) throw err;
-                db.get("SELECT big AS bigint FROM bigint_table", function (err, row) {
-                    if (err) throw err
-                    assert.equal(row.bigint, bigint);
-                    done();
+    if (process.versions.napi >= '6') {
+        [
+            1n,
+            1337n,
+            8876343627091516928n,
+            -8876343627091516928n,
+        ].forEach(function (bigint) {
+            it('should serialize BigInt ' + bigint, function (done) {
+                db.run("INSERT INTO bigint_table VALUES(?)", bigint, function(err) {
+                    if (err) throw err;
+                    db.get("SELECT big AS bigint FROM bigint_table", function (err, row) {
+                        if (err) throw err
+                        assert.equal(row.bigint, bigint);
+                        done();
+                    });
                 });
             });
         });
-    });
+    }
 
     it('should fail to serialize larger numbers', function (done) {
         const bigint = 0xffffffffffffffffffffn; // 80 bits