braces

a control flow body that is a single statement has no braces

Applies to the block owned by an if (the consequent or the else) and by any loop, at any depth, module top level included. When the block holds exactly one statement of a removable kind (an expression, return, throw, break, continue, a nested if or a loop), the braces go. Only the braces go: Stanza never reflows the code inside, so a body that sat on its own line stays there, and line breaking is left to your formatter. do { tick(); } while (busy) loses its braces too.

Braces stay when:

• the block holds anything other than exactly one statement, an empty block included;
• the statement is a declaration (const, let, var, a function, a class), a nested block, a switch, a try, a labeled statement or an empty statement;
• the statement has no trailing ; and the next code could continue it: the next token is on the same line, or the next line starts with (, [, a backtick, +, -, /, ., < or ;;
• a comment sits inside the braces but outside the statement, like // drop the last one in the second example;
• a comment follows a } that sits alone on its line, as in } // note;
• removing them would leave a dangling else: the statement ends with an if that has no else, and an else follows the block, as in the second example;
• removing them would fuse two words, as in else{a();};
• the unbraced text would no longer parse.

A statement under stanza-ignore keeps its own braces, else if chain and label included, while the code nested inside it is still formatted (see Directives). --no-braces turns the rule off, and so does a lint config that enforces braces. Braces and Lint Config covers both.

Removing braces changes which statements are compact, so the blank line rules see the unbraced code. When unbracing leaves a body of two or three compact statements, short-body removes the blank lines between them.

ExampleCopy Anchor Link

function retry(task: Task, attempts: number) {
  if (attempts === 0) {
    throw new Error(`${task.name} failed`);
  }

  while (!task.done) {
    task.run();
  }

  for (const listener of task.listeners) {
    listener.notify(task);
    listener.close();
  }
}

function retry(task: Task, attempts: number) {
  if (attempts === 0)
    throw new Error(`${task.name} failed`);

  while (!task.done)
    task.run();

  for (const listener of task.listeners) {
    listener.notify(task);
    listener.close();
  }
}

Braces That StayCopy Anchor Link

The else branch loses its braces. The outer if keeps them because its body ends in an if without else, and the while keeps them because of the comment.

function pick(items: Item[], strict: boolean) {
  if (items.length > 1) {
    if (strict) log("many");
  } else {
    log("one");
  }

  while (items.length > 0) {
    // drop the last one
    items.pop();
  }
}

function pick(items: Item[], strict: boolean) {
  if (items.length > 1) {
    if (strict) log("many");
  } else
    log("one");

  while (items.length > 0) {
    // drop the last one
    items.pop();
  }
}