[Fixed] chaining operator throwing error in express app

Issue

I am trying to use the optional chaining operator (?.) in my express app – it throws error whenever i try.

if (user.address?.postal_code.length > 0 ) {
                 ^

SyntaxError: Unexpected token '.'
    at wrapSafe (internal/modules/cjs/loader.js:1053:16)

I have tried all variations

user?.address?.postal_code?.length
user?.address?.postal_code.length
user?.address.postal_code.length


"engines": {
        "node": "10.16.0",
        "npm": "6.9.0"
    },
    "dependencies": {
        "body-parser": "^1.19.0",
        "express": "^4.17.1",
        ...
    }

Solution

You have 2 options

1. Upgrade your Node version. Only these versions support optional chaining. As you can see, only Node 14.5+ supports optional chaining
2. If you want to support older versions such as 12, you will need to transpile your code. Take a look at Babel or TypeScript. These programs take your code and transform it into code that is compatible with older Node versions. For example, your code:

if (user.address?.postal_code.length > 0 ) {
    // Do stuff
}

Turns into:

var _user$address;

if (((_user$address = user.address) === null || _user$address === void 0 ? void 0 : _user$address.postal_code.length) > 0) {
    // Do stuff
}