To fix Node.js: SyntaxError: Cannot use import statement outside a module error, we use CommonJS modules.
For instance, we write
module.exports.func = () => {
console.log("Hello World");
};
to define the func function and export it in mod.js.
Then we write
const myMod = require("./mod");
myMod.func();
to call require to require mod.js.
And we call myMod.func to call the function.
To call Node.js "require" function and parameters, we export a function.
For instance, we write
module.exports = (options) => {
const app = options.app;
const param2 = options.param2;
};
in lib.js to export a function.
Then we write
require("lib.js")({ app, param2 });
to require the lib.js file and call the function that’s imported.
To toggle between multiple .env files like .env.development with Node.js, we use the dotenv library.
For instance, we write
require("dotenv").config({ path: `.env.${process.env.NODE_ENV}` });
to call config with an object with the path property to point to the .env file path we want to use.
process.env.NODE_ENV is the NODE_ENV environment variable value.
To convert string to number with Node.js, we call the parseInt function.
For instance, we write
const year = parseInt(req.params.year, 10);
to call parseInt to convert req.params.year to a decimal integer.
To update npm on Windows, we run npm install.
We run
npm install npm@latest
to update npm to the latest version.