_ModelOptions removed from instance in V6

[WaylonOKC]

Issue Description

In Sequelize v5, my instance would look like:

recentItem {
  dataValues: {
    id: 't4qupOzsuPrxLuHkLiYwA',
    createdAt: 2019-07-23T22:07:43.727Z,
    updatedAt: 2020-07-08T19:30:13.348Z,
    entityId: 'SJleJVAA_z'
  },
  _previousDataValues: {
    id: 't4qupOzsuPrxLuHkLiYwA',
    createdAt: 2019-07-23T22:07:43.727Z,
    updatedAt: 2020-07-08T19:30:00.122Z,
    entityId: 'SJleJVAA_z'
  },
  _changed: { updatedAt: true },
  _modelOptions: {
    timestamps: true,
    validate: {},
    freezeTableName: false,
    underscored: false,
    paranoid: false,
    rejectOnEmpty: false,
    whereCollection: {
      entityId: 'SJleJVAA_z'
    },
    schema: null,
    schemaDelimiter: '',
    defaultScope: {},
    scopes: {},
    indexes: [],
    name: { plural: 'recentItems', singular: 'recentItem' },
    omitNull: false,
    sequelize: Sequelize {
      options: [Object],
      config: [Object],
      dialect: [PostgresDialect],
      queryInterface: [QueryInterface],
      models: [Object],
      modelManager: [ModelManager],
      connectionManager: [ConnectionManager],
      importCache: [Object],
      Op: [Object],
      Promise: [Function]
    },
    hooks: {}
  },
  _options: {
    isNewRecord: false,
    _schema: null,
    _schemaDelimiter: '',
    raw: true,
    attributes: [ 'id', 'createdAt', 'updatedAt', 'entityId' ]
  },
  isNewRecord: false
}

In Sequelize v6, I do not have the _modelOptions. How can I get the model information (_modelOptions)? It's needed because the instance could be one of several different models.

StackOverflow / Slack attempts

StackOverflow Question

Issue Template Checklist

Is this issue dialect-specific?

• No. This issue is relevant to Sequelize as a whole.
• Yes. This issue only applies to the following dialect(s): XXX, YYY, ZZZ
• I don't know.

Would you be willing to resolve this issue by submitting a Pull Request?

• Yes, I have the time and I know how to start.
• Yes, I have the time but I don't know how to start, I would need guidance.
• No, I don't have the time, although I believe I could do it if I had the time...
• No, I don't have the time and I wouldn't even know how to start.

[sushantdhiman]

Use instance.constructor.options

[WaylonOKC]

Thanks!

[jalopez526]

Use instance.constructor.options

Have this been written on docs? I spent some hours looking for something like this.