Category: JavaScript Answers

To pass variable from jade template file to a script file with JavaScript, we pass in the variable to the template with render.

For instance, in our Jade template, we write

script.
  loginName="#{login}";

Then we write

exports.index = (req, res) => {
  res.render("index", { layout: false, login: req.session.login });
};

to call res.render with an object with the login property set to the value we want to pass to the Jade template.

To clone a JavaScript ES6 class instance, we use a few object methods.

For instance, we write

const clone = Object.assign(Object.create(Object.getPrototypeOf(orig)), orig);

to get the prototype of the orig object with Object.getPrototypeOf.

Then we create a new object from the prototype with Object.create.

Then we call Object.assign to make a copy of the object we created and return it.

To require file as string with Node.js, we call readFileSync.

For instance, we write

import fs from "fs";
import path from "path";

const css = fs.readFileSync(path.resolve(__dirname, "email.css"), "utf8");

to read the email.css file into a string with the readFileSync method.

To fix Unknown column ‘*.createdAt’ in ‘field list’ error with Node.js Sequelize, we add a model with the createdAt field.

For instance, we write

const users = sequelize.define("users", {
  id: {
    type: Sequelize.INTEGER,
    primaryKey: true,
  },
  createdAt: {
    field: "created_at",
    type: Sequelize.DATE,
  },
  updatedAt: {
    field: "updated_at",
    type: Sequelize.DATE,
  },
  //...
});

to add the createdAt field to the users model and map it toi the created_at date field.

To do batch insert with Node.js MongoDB Mongoose, we call the insertMany method.

For instance, we write

const rawDocuments = [
  /* ... */
];

const mongooseDocuments = await Book.insertMany(rawDocuments);

to call the insertMany method in the Book schemas to insert the rawDocuments into the database.