To turn all the keys of an object to lower case with JavaScript, we use some object methods.
For instance, we write
const newObj = Object.fromEntries(
Object.entries(obj).map(([k, v]) => [k.toLowerCase(), v])
);
to call Object.entries to return an array of key-valye pair arrays from the obj.
Then we call map with a callback to map the keys to lower case with toLowwerCase and v.
And then we call Object.fromEntries to convert the mapped key-value pair array back to an object.
To ignore incompatible engine "node" error on installing npm dependencies with yarn, we remove the engines entry from the package.json file.
We can also run
yarn config set ignore-engines true
to ignore the engines entry in package.json once by setting the ignore-engines setting to true.
To remove all properties from a object with Node.js, we assign the variable to an empty object.
For instance, we write
req.session = {};
to assign req.session to an empty object to remove all properties from it.
To fix "Error: Cannot find module ‘ejs’ " with Node.js, we install the ejs library.
To install it, we run
npm install ejs
in our project folder to install the ejs package with npm.
To define an array as an environment variable in Node.js, we can define it as a JSON array.
For instance, we write
ANY_LIST = ["A", "B", "C"]
to add the ANY_LIST environment variable to our .env file.
Then we write
const LIST = JSON.parse(process.env.ANY_LIST);
to get the ANY_LIST environment variable with process.env.ANY_LIST.
And we parse it into an array with JSON.parse.