@putout/plugin-apply-optional-chaining

The optional chaining operator (?.) enables you to read the value of a property located deep within a chain of connected objects without having to check that each reference in the chain is valid.

The ?. operator is like the . chaining operator, except that instead of causing an error if a reference is nullish (null or undefined), the expression short-circuits with a return value of undefined. When used with function calls, it returns undefined if the given function does not exist.

This results in shorter and simpler expressions when accessing chained properties when the possibility exists that a reference may be missing. It can also be helpful while exploring the content of an object when there's no known guarantee as to which properties are required.

(c) MDN

🐊Putout plugin applies optional chaining. Backward to convert-optional-to-logical.

Install

npm i @putout/plugin-apply-optional-chaining

Rule

{
    "rules": {
        "apply-optional-chaining/use": "on",
        "apply-optional-chaining/assign": "off"
    }
}

use

Checkout out in 🐊Putout Editor.

❌ Example of incorrect code

const result = hello && hello.world;

if (typeof a === 'function' && a(1, 2))
    alert();

✅ Example of correct code

const result = hello?.world;

if (a?.(1, 2))
    alert();

assign

Proposal to add support for optional chaining on the left of assignment operators: a?.b = c.

(c) Proposal of Optional Chaining Assignment

Disabled by default. Checkout out in 🐊Putout Editor.

❌ Example of incorrect code

if (a) {
    a.b = 5;
}

if (a)
    a.b = 5;

a && (a.b = 5);

✅ Example of correct code

a?.b = 5;

License

MIT