require an empty line before return statements (newline-before-return)

The --fix option on the command line can automatically fix some of the problems reported by this rule.

This rule was deprecated in ESLint v4.0.0 and replaced by the padding-line-between-statements rule.

There is no hard and fast rule about whether empty lines should precede return statements in JavaScript. However, clearly delineating where a function is returning can greatly increase the readability and clarity of the code. For example:

function foo(bar) {
  var baz = 'baz';
  if (!bar) {
    bar = baz;
    return bar;
  }
  return bar;
}

Adding newlines visibly separates the return statements from the previous lines, making it clear where the function exits and what value it returns:

function foo(bar) {
  var baz = 'baz';

  if (!bar) {
    bar = baz;

    return bar;
  }

  return bar;
}

Rule Details

This rule requires an empty line before return statements to increase code clarity, except when the return is alone inside a statement group (such as an if statement). In the latter case, the return statement does not need to be delineated by virtue of it being alone. Comments are ignored and do not count as empty lines.

Examples of incorrect code for this rule:

/*eslint newline-before-return: "error"*/

function foo(bar) {
    if (!bar) {
        return;
    }
    return bar;
}

function foo(bar) {
    if (!bar) {
        return;
    }
    /* multi-line
    comment */
    return bar;
}

Examples of correct code for this rule:

/*eslint newline-before-return: "error"*/

function foo() {
    return;
}

function foo() {

    return;
}

function foo(bar) {
    if (!bar) return;
}

function foo(bar) {
    if (!bar) { return };
}

function foo(bar) {
    if (!bar) {
        return;
    }
}

function foo(bar) {
    if (!bar) {
        return;
    }

    return bar;
}

function foo(bar) {
    if (!bar) {

        return;
    }
}

function foo() {

    // comment
    return;
}

When Not To Use It

You can safely disable this rule if you do not have any strict conventions about whitespace before return statements.

Related Rules

• newline-after-var

Version

This rule was introduced in ESLint 2.3.0.

Resources

• Rule source
• Documentation source