(Sequelize) Using A Model By Name Dynamically - node.js

Question

I'm wondering if it is possible with Sequelize to create the needed models and then use one based on a value received from a request. I've tried different means to accomplish this but not finding a working solution. I accept it may not exist. But if so, does anyone have ideas on how to accomplish this?
const express = require('express');
const router = express.Router();
const Models = require('../models');
...
for (let modelName in tablesObj) {
if (modelName == primaryTable) {
Models.modelName.findAll()
.then(results => {
console.log(result);
});
}
}

Answer 1

The best way to do this is in your loader in the /models directory. It can export an object of Models keyed by the model name.
models/index.js
const fs = require('fs');
const path = require('path');
const sequelize = // your db connection
// object to hold all the models to export
const models = {};
// Read all the files from this dir and load the models
fs.readdirSync(__dirname)
.forEach((file) => {
if (file !== path.basename(__filename) && file.endsWith('.js')) {
const model = sequelize.import(
path.join(__dirname, '/', file.replace(/\.js$/, ''))
);
models[model.name] = model;
}
});
/* anything else you want to do goes here */
// export the models
module.exports = models;
Now you can load the models and then access each one by the name.
other.js
const models = require('../models');
async function runQuery() {
// access "modelName" model
const result = await models.modelName.findByPk(1);
// rest of your method
}
I usually take this a step further and load the models into the file that creates the Express app, then set the models to a property on the app and pass that around to routers.
server.js
const Express = require('express');
const models = require('./models');
const app = new Express();
app.model = (model) => models[model];
Now you can access your models like so:
// assuming the model name is "Widget"
const widget = await app.models('Widget').findOne(...);

Answer 2

For me, there was no need to add/modify the index.js file. The index.js was already present inside models folder by default.
Below code works for me!!,
const models = require("../../models");
let modeName, runningModel;
router.get('/api/:module', (req, res) => {
modelName = (req.params.module)
runningModel = models[modelName];
runningModel.findAndCountAll({
//your code goes here
})
.then(resutls => res.json(results)
.catch(err => res.json(err);
}
The following are the package and version used in my project
"express": "^4.17.1",
"morgan": "^1.10.0",
"pg": "^8.2.1",
"sequelize": "^5.21.4",
"sequelize-cli": "^5.5.1"