Proposal: Require an empty line between "switch-case" statements (newline-between-switch-case)

Proposal:

Require an empty line between switch-break statements (newline-between-switch-break) #6619 (newline-between-switch-break)

Options

This rule has an object option:

• "spaceAfterBreak": true (default).
• "spaceBeforeBreak": false

Relative

• The curlies should be covered by padded-blocks.

switch (value) {

     case 100000000000000:
          break;

    default:
          break;

}

• Comments should be covered by lines-around-comment:

For consistency reasons comments are ignored and do not count as empty lines.

switch (value) {
     case 100000000000000:
          break;

    // comment
    default:
          break;
}

Examples

/*eslint newline-between-switch-break: "error"*/ or /*eslint newline-between-switch-break: [ "error", {"spaceAfterBreak": true }]*/

Example of correct code for this rule:

switch (value) {
     case 100000000000000:
          break;

     case 200000000000000:
          break;

     default:
          break;
 }

Example of incorrect code for this rule:

switch (value) {
     case 100000000000000:
          value
          break;
     case 200000000000000:
          break;
     default:
          break;
 }

/*eslint newline-between-switch-break: ["error", { "spaceBeforeBreak": true }]*/

switch (value) {
     case 100000000000000:
          value += 100;

          break;
 }

Example of incorrect code for this rule:

switch (value) {
     case 100000000000000:
          value += 100;
          break;
 }

[btmills]

Nice examples! That helps clarify the problem. I’m envisioning the newline-before-return equivalent for break and continue as being almost identical to the return version, specifically in that it would exclude any statement that is alone in its block.

What about this?

• "newline-before-flow-control": ["error", "always/never"]: require an empty line before break or continue statements
• "newline-between-switch-case": ["error", "always/never", { "fallthrough": "never"}]: require an empty line between the cases (and default), if present) of a switch statement. The object argument for fallthrough would only be applicable if the rule were set to "always".

/*eslint newline-before-flow-control: ["error", "always"]*/
/*eslint newline-between-switch-case: ["error", "always", { "fallthrough": "never" }]*/
switch (foo) {
    case a: // newline before (or lack thereof) is controlled by padded-blocks
        doSomething();

        break; // newline before because `break` follows another statement

    case b: // newline before because newline-between-switch-case "always"
        break; // no newline before because `break` is alone in the `case`

    case c: // newline before because newline-between-switch-case "always"
    case d: // no newline before because newline-between-switch-case fallthrough "never"
        doAnotherThing();

        break; // newline before because `break` follows another statement

    default: // newline before because newline-between-switch-case "always"
        throw new Error("This should never happen");
}

for (let i = 0; i < arr.length; i++) {
    if (goodEnough(arr[i])) {
        break; // no newline before because `break` is alone in the block
    }
}

// Your examples with these options:
switch (value) {
     case 100000000000000:
          break; 

     case 200000000000000:
          value += 1;

          break; 

     default:
          break; 
}

for (let index of [, ]) {
    if (index++) {
        break;
    } 
}

for (let index of [, ]) {
    if (index++)
        break;

    continue;
}

for (let i of [, ]) {
    break;
}

for (let i of [, ]) 
    break;

// You had `for (let i of [, ]); break;`, meaning `break` is not in the loop. Was that intentional? I'll do both.
for (let i of [, ]);

break; 

for (let i of [, ]) break;

Is that code formatted more like what you want?

[lukeapage]

I wanted this rule (newline-between-switch-case), but didn’t want to wait for this to be accepted, so have implemented in a plugin - https://github.com/lukeapage/eslint-plugin-switch-case Please feel free to use the code as the basis for putting this rule in core (might need a bit more tidying/documentation/code formatting)