typescript - Sequelize.js:Model.build 返回一个空白对象

Question

我正在使用 Sequelize.js (4.38.0) 和 Typescript (3.0.3)。我还安装了包 @types/sequelize(版本 4.27.25)。

我有以下无法转译的代码:

import Sequelize from 'sequelize'

const sequelize = new Sequelize('...');
const model = sequelize.define('Model', {a: Sequelize.INTEGER, b: Sequelize.INTEGER});

var instance = model.build({a: 1, b:1});
instance.save();

tsc 返回以下错误:

 Property 'save' does not exist on type '{}'.

所以出于某种原因， build 返回一个空白对象。
当我尝试使用 create 时，出现相同的错误:create 返回一个 Promise 来解析一个空白对象。

对此有什么想法吗？

Answer 1

您需要明确指定泛型类型参数，定义不会尝试推断属性或实例类型的类型。

import Sequelize, { Instance } from 'sequelize'

const sequelize = new Sequelize('...');

interface Model {
    a: number;
    b: string;
}


const model = sequelize.define<Instance<Model>, Model>('Model', {a: Sequelize.INTEGER, b: Sequelize.INTEGER});

var instance = model.build({a: 1, b:'1'}); // b must be string error is now caught by typescript 
instance.save() // ok now