arrow-body-style

x => x * 2 and x => { return x * 2; } do the same thing. By default, this rule reports the braces when the body is nothing but one return, so short functions stay short.

--fix removes or adds the braces and the return.

Configure

Off by default. To turn it on:

[lint.rules]
"arrow-body-style" = "error" # or "warn"

Every option, set to its default. The ones that are commented out are unset by default.

[lint.rules]
"arrow-body-style" = [
  "error",
  "as-needed", # "always", "never" or "as-needed"
  {
    # requireReturnForObjectLiteral = <true or false>,
  },
]

Examples

Reported:

const double = items.map(item => {
  return item * 2;
});

Not reported:

const double = items.map(item => item * 2);

const logged = items.map(item => {
  console.log(item);
  return item * 2;
});

Options

[lint.rules]
arrow-body-style = ["error", "always"]

Option	What it does
"as-needed" (default)	Report braces around a body that's only a return.
"always"	Report every arrow function without braces.
"never"	Report every arrow function with braces, no matter what's in them. --fix only rewrites a body that's a single return.

const double = items.map(item => item * 2);

const logged = items.map(item => {
  console.log(item);
  return item * 2;
});

With "as-needed", a second option { "requireReturnForObjectLiteral": true } (default false) requires braces and a return when the function returns an object literal, instead of => ({ ... }).

const toPoint = item => ({ x: item.left, y: item.top });

const toPoint = item => {
  return { x: item.left, y: item.top };
};