Rule Enhancement Proposal: object-property-newline with never and some options

From disallowObjectKeysOnNewLine.

I had forgotten to make this proposal in my previous vacation.

JSCS has disallowObjectKeysOnNewLine rule, but object-property-newline rule doesn’t support it, so I think we need to add "always"/"never" and some other options into object-property-newline rule. It would be similar options to #6072, #6073, and #6075. These options are “conditions to need line breaks”. I like consistency, so I hope this proposal’s option will be so also.

There are too many options in this proposal. In my head, those are for autofix.

---

(fixable) The --fix option on the command line automatically fixes problems reported by this rule.

Options

{
    "object-property-newline": [
        "error",
        {"allowMultiplePropertiesPerLine": false}
    ],
    // OR
    "object-property-newline": [
        "error",
        "always" or "never" or {"multiline": false, "minProperties": 0, "minNonShorthandProperties": 0},
        {"allowMultiplePropertiesPerLine": false}
    ]
}

1st option: when does it require line breaks between properties?

• "always" (default) - requires line breaks always.
• "never" - disallows line breaks always.
• An object - requires line breaks if any of the following conditions are satisfied. Otherwise, disallows line breaks.
  • multiline (default is false) - requires line breaks if there are line breaks inside of properties. If this is false, this condition is disabled.
  • minProperties (default is 0) - requires line breaks if the number of properties is more than the given integer. If this is 0, this condition is disabled.
  • minLongformProperties (default is 0) - requires line breaks if the number of non-shorthand properties is more than the given integer. If this is 0, this condition is disabled. (#6211)

2nd option:

• allowMultiplePropertiesPerLine (default is false) - allows all keys and values to be on the same line.

always

Examples of incorrect code for this rule with the "always" option:

/*eslint object-property-newline: ["error", "always"]*/
/*eslint-env es6*/

let c = {foo: 1, bar: 2};
let d = {foo: 1, bar: 2, baz: 3};
let e = {foo, bar, baz};
let f = {
    foo, bar() {
        dosomething();
    }
};

Examples of correct code for this rule with the "always" option:

/*eslint object-property-newline: ["error", "always"]*/
/*eslint-env es6*/

let a = {};
let b = {foo: 1};
let c = {foo: 1,
    bar: 2};
let d = {foo: 1,
    bar: 2,
    baz: 3};
let e = {foo,
    bar,
    baz};
let f = {
    foo,
    bar() {
        dosomething();
    }
};

never

Examples of incorrect code for this rule with the "never" option:

/*eslint object-property-newline: ["error", "never"]*/
/*eslint-env es6*/

let c = {foo: 1,
    bar: 2};
let d = {foo: 1,
    bar: 2,
    baz: 3};
let e = {foo,
    bar,
    baz};
let f = {
    foo,
    bar() {
        dosomething();
    }
};

Examples of correct code for this rule with the "never" option:

/*eslint object-property-newline: ["error", "never"]*/
/*eslint-env es6*/

let a = {};
let b = {foo: 1};
let c = {foo: 1, bar: 2};
let d = {foo: 1, bar: 2, baz: 3};
let e = {foo, bar, baz};
let f = {
    foo, bar() {
        dosomething();
    }
};

multiline

Examples of incorrect code for this rule with the {"multiline": true} option:

/*eslint object-property-newline: ["error", {"multiline": true}]*/
/*eslint-env es6*/

let c = {foo: 1,
    bar: 2};
let d = {foo: 1,
    bar: 2,
    baz: 3};
let e = {foo,
    bar,
    baz};
let f = {
    foo, bar() {
        dosomething();
    }
};

Examples of correct code for this rule with the {"multiline": true} option:

/*eslint object-property-newline: ["error", {"multiline": true}]*/
/*eslint-env es6*/

let a = {};
let b = {foo: 1};
let c = {foo: 1, bar: 2};
let d = {foo: 1, bar: 2, baz: 3};
let e = {foo, bar, baz};
let f = {
    foo,
    bar() {
        dosomething();
    }
};

minProperties

Examples of incorrect code for this rule with the {"minProperties": 3} option:

/*eslint object-property-newline: ["error", {"minProperties": 3}]*/
/*eslint-env es6*/

let c = {foo: 1,
    bar: 2};
let d = {foo: 1, bar: 2, baz: 3};
let e = {foo, bar, baz};
let f = {
    foo,
    bar() {
        dosomething();
    }
};

Examples of correct code for this rule with the {"minProperties": 3} option:

/*eslint object-property-newline: ["error", {"minProperties": 3}]*/
/*eslint-env es6*/

let a = {};
let b = {foo: 1};
let c = {foo: 1, bar: 2};
let d = {foo: 1,
    bar: 2,
    baz: 3};
let e = {foo,
    bar,
    baz};
let f = {
    foo, bar() {
        dosomething();
    }
};

minLongformProperties

Examples of incorrect code for this rule with the {"minLongformProperties": 3} option:

/*eslint object-property-newline: ["error", {"minLongformProperties": 3}]*/
/*eslint-env es6*/

let c = {foo: 1,
    bar: 2};
let d = {foo: 1, bar: 2, baz: 3};
let e = {foo,
    bar,
    baz};
let f = {
    foo,
    bar() {
        dosomething();
    }
};

Examples of correct code for this rule with the {"minLongformProperties": 3} option:

/*eslint object-property-newline: ["error", {"minLongformProperties": 3}]*/
/*eslint-env es6*/

let a = {};
let b = {foo: 1};
let c = {foo: 1, bar: 2};
let d = {foo: 1,
    bar: 2,
    baz: 3};
let e = {foo, bar, baz};
let f = {
    foo, bar() {
        dosomething();
    }
};

a combination of multiline and minLongformProperties

Examples of incorrect code for this rule with the {"multiline": true, "minLongformProperties": 3} option:

/*eslint object-property-newline: ["error", {"multiline": true, "minLongformProperties": 3}]*/
/*eslint-env es6*/

let c = {foo: 1,
    bar: 2};
let d = {foo: 1, bar: 2, baz: 3};
let e = {foo,
    bar,
    baz};
let f = {
    foo, bar() {
        dosomething();
    }
};

Examples of correct code for this rule with the {"multiline": true, "minLongformProperties": 3} option:

/*eslint object-property-newline: ["error", {"multiline": true, "minLongformProperties": 3}]*/
/*eslint-env es6*/

let a = {};
let b = {foo: 1};
let c = {foo: 1, bar: 2};
let d = {foo: 1,
    bar: 2,
    baz: 3};
let e = {foo, bar, baz};
let f = {
    foo,
    bar() {
        dosomething();
    }
};

Related Rules

	brace style	space style	line break style
block	brace-style	block-spacing	max-statements-per-line
object	#6072 object-curly-newline	object-curly-spacing	object-property-newline
array	#6073 array-bracket-newline	array-bracket-spacing	#6075 array-element-newline

• comma-spacing

[platinumazure]

@eslint/eslint-team Can we get more eyes on this proposal?

I’m a little leery of the number of options (only in terms of, is this worth doing as multiple issues/PRs?), but that’s not a huge issue. But we should really make sure we get the option names right.

I’m going to offer one slightly different schema: In order to emphasize that most of the options are conditions for requiring the property newline, maybe they could be grouped in an object with a key indicating that? (I’ve also changed some of the other keys, but I’m not strongly attached to these names.)

{
    "object-property-newline": ["error", {
        "requiredWhen": {
            "propertyCount": 3,           // Equivalent to minProperties
            "longformPropertyCount": 3,   // Equivalent to minLongformProperties
            "hasMultilineProperty": true  // Equivalent to multiline
        }
    }
}

[nijikokun]

Rip