@putout/plugin-assignment

The assignment operator (=) is used to assign a value to a variable. The assignment operation evaluates to the assigned value. Chaining the assignment operator is possible in order to assign a single value to multiple variables.

🐊Putout plugin adds ability to transform to new Node.js API and apply best practices.

Install

npm i putout @putout/plugin-assignment -D

Rules

• ✅ convert-to-arrow-function;
• ✅ convert-to-comparison;
• ✅ convert-to-declaration;
• ✅ simplify;
• ✅ split;

Config

{
    "rules": {
        "assignment/convert-to-arrow-function": "on",
        "assignment/convert-to-comparison": "on",
        "assignment/convert-to-declaration": "on",
        "assignment/simplify": "on",
        "assignment/split": "on"
    }
}

convert-to-arrow-function

An arrow function expression is a compact alternative to a function expression.

(c) MDN

Rule adds ability to convert assignment to arrow function.

❌ Example of incorrect code

const createRegExp = a = RegExp(a, 'g');

✅ Example of correct code

const createRegExp = (a) => RegExp(a, 'g');

convert-to-comparison]

You should almost never have an if...else with an assignment like a = b as a condition.

(c) MDN

❌ Example of incorrect code

if (a = b) {}

✅ Example of correct code

if (a === b) {}

convert-to-declaration

The const declaration declares block-scoped local variables. The value of a constant can't be changed through reassignment using the assignment operator, but if a constant is an object, its properties can be added, updated, or removed.

(c) MDN

Checkout in 🐊Putout Editor.

❌ Example of incorrect code

a = 5;

✅ Example of correct code

const a = 5;

simplify

❌ Example of incorrect code

const {a} = {
    a: 5,
};

const [b] = [5];
const c = (() => 7)();

✅ Example of correct code

const a = 5;
const b = 5;
const c = 7;

split

Rule adds ability to find and split variable declarations because (re)moving a line is simpler and less error prone then changing coma (=) to colon (;).

For the same reason, diff of changed declarations are more comfortable to read. Checkout in 🐊Putout Editor.

❌ Example of incorrect code

a = b = c = 1;

✅ Example of correct code

a = 1;
b = a;
c = a;

License

MIT