这显然取决于如何初始化连接。
如果您遵循了docs链接上的教程（检查配置文件部分），那么您可以将用户名声明为root，密码声明为null。

{
    "development": {
        "username": "root",
        "password": null,
        "database": "database_development",
        "host": "127.0.0.1",
        "dialect": "mysql"
    },
    "test": {
        "username": "root",
        "password": null,
        "database": "database_test",
        "host": "127.0.0.1",
        "dialect": "mysql"
   },
    "production": {
        "username": "root",
        "password": null,
        "database": "database_test",
        "host": "127.0.0.1",
        "dialect": "mysql"
   }
}

现在，如果您只是示例化一个sequelize对象，您可以完全像下面那样跳过password参数。检查设置连接部分上的此链接。

const Sequelize = require('sequelize');
const sequelize = new Sequelize('database', 'username', null, {
   host: 'localhost',
   dialect: 'mysql' | 'sqlite' | 'postgres' | 'mssql',
       operatorsAliases: false,
   pool: {
       max: 5,
       min: 0,
       acquire: 30000,
       idle: 10000
   },
});