Allow padding on simple returns for newline-before-return

[andrewvaughan]

ESLint Version: 2.10.1

Problem:

Using newline-before-return with padded-blocks causes a conflict, as padded-blocks insists on padded spacing for functions, and newline-before-return complains if there is a newline before a return statement by itself in a function.

Recommended Solution:

Add an option to newline-before-return to ignore scenarios where the only statement in a function block is the return statement.

For example:

"newline-before-return": ["error", {
    "pad-getters": true  // (New) Ensure getter returns are padded on either side by a newline
}]

This will allow ESLint to properly support it's built-in plugins without changing the default functionality of the newline-before-return rule. With the above configuration:

This code would result in an error:

function getVar() {
    return this.var;
}

This code would be valid with both plugins:

function getVar() {

    return this.var;

}

[alberto]

I think newline-before-return should not error when it is the first statement in a block, regardless of the newlines and that should be left to padded-blocks.

The doc says (emphasis mine):

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.

[kaicataldo]

I support @alberto's suggested change 👍, though this would be a breaking change to the rule. I wonder if we should make it an option that relaxes the rule for that case?

[mysticatea]

I added accepted label since there are 4 👍s from core team.

[alberto]

There is still the question of whether this is a breaking change and it should instead be treated as an enhancement go behind an option @eslint/eslint-team

There are a good number of tests asserting this behaviour

[mysticatea]

I think we can modify the default behavior because this change is relaxing, so it probably will not break existing CI tests of users.

[mikesherov]

In JSCS, relaxing rules was not considered a breaking change.

[markelog]

Can we document what should be considered as breaking change? See JSCS example https://github.com/jscs-dev/node-jscs/blob/master/OVERVIEW.md#user-content-versioning--semver for reference

[nzakas]

I concur that this is a bug as the documentation seems to indicate that the desired behavior.

I've opened an issue so we can discuss formalizing a semver policy: #6244

[kalisjoshua]

I like this as an option. When should this be available? It looks like it is already included but I am not seeing it working.

[kaicataldo]

Hey there, this should be in as of >2.11.0 http://eslint.org/blog/2016/05/eslint-v2.11.0-released#bug-fixes

[kalisjoshua]

@kaicataldo That's what I was thinking but I am not able to get this option to work; I still get:

error  Block must not be padded by blank lines  padded-blocks

... in my lint results output.

My .eslintrc.json looks like this:

{
  "env": {
    "browser": true,
    "node": true
  },
  "extends": "airbnb",
  "rules": {
    "comma-dangle": ["warn", "never"],
    "consistent-return": "error",
    "eqeqeq": ["error", "smart"],
    "newline-before-return": "off",
    "no-use-before-define": ["error", {
      "functions": false
    }],
    "space-before-function-paren": ["warn", "always"]
  }
}

I've tried all permutation of newline-before-return and padded-blocks. The only thing that seems to be working is padded-blocks which affects everything and I only want to allow an additional line before return statements. Am I understanding this correctly?

[kaicataldo]

Ah yeah, that's the padded-blocks rule warning, not the newline-before-return rule. I recommend making a new issue for this, since this issue is unrelated and closed. Please make sure you include the info asked for in the template, including the code that's throwing the error. Thanks!

[kalisjoshua]

@kaicataldo Correct, it is the padded-blocks error message but shouldn't the option proposed by this feature relax that? Am I misunderstanding the purpose of this additional option?

update: Here is a repo I put together to illustrate the issue - https://github.com/kalisjoshua/eslint-bug-example.

[kaicataldo]

Looks like this fix was just for newlines before return statements. The padded-blocks warning is for the missing newline after the return statement (on line 4 in your example). The change in this issue makes the rules compatible by relaxing the newline-before-return rule to allow a newline before the return statement even when it's the only statement in the block. It sounds like you might not want to be using the padded-blocks rule, if you don't want a padding newline before the end of the block.