unicorn/no-unreadable-iife

(() => (value))() ends in a pile of parentheses. It's hard to see which pair closes the body, which closes the function and which calls it. A block body with return reads better. Often you don't need the function at all.

--fix-suggestions turns the body into { return ...; }.

Configure

Off by default. To turn it on:

[lint.rules]
"unicorn/no-unreadable-iife" = "error" # or "warn"

Examples

Reported:

const label = (() => (count === 1 ? "item" : "items"))();

Not reported:

const label = (() => {
  return count === 1 ? "item" : "items";
})();

const plain = count === 1 ? "item" : "items";

// no parentheses around the body
const now = (() => Date.now())();

// not called in place
const toPoint = (x, y) => ({ x, y });