function testSyntaxError(script, message) { var error = null; try { eval(script); } catch (e) { error = e; } if (!error) throw new Error("Expected syntax error not thrown"); if (String(error) !== message) throw new Error("Bad error: " + String(error)); } testSyntaxError(`V={=>`, `SyntaxError: Unexpected token '=>'. Expected a property name.`);