unicorn/no-array-reduce

To read a reduce(), you have to follow the accumulator through every return in the callback, and its starting value comes last, after the callback. Written as a for...of loop, the same code names the result first and updates it in plain statements.

A callback that only combines two values with an operator, such as a sum, is allowed by default.

Configure

Off by default. To turn it on:

[lint.rules]
"unicorn/no-array-reduce" = "error" # or "warn"

Every option, set to its default:

[lint.rules]
"unicorn/no-array-reduce" = ["error", {
  allowSimpleOperations = true,
}]

Examples

Reported:

const byId = users.reduce((result, user) => {
  result[user.id] = user;
  return result;
}, {});

Not reported:

const byId = {};
for (const user of users) {
  byId[user.id] = user;
}

const total = prices.reduce((sum, price) => sum + price, 0);

Options

const total = prices.reduce((sum, price) => sum + price, 0);