eslint-plugin-canonical

eslint-plugin-canonical

ESLint rules for Canonical ruleset.

• eslint-plugin-canonical
  • Installation
  • Configuration
    • Shareable configurations
  • Rules
    • filename-match-exported
    • filename-match-regex
    • filename-no-index
    • id-match
    • no-restricted-strings
    • sort-keys

Installation

npm install eslint --save-dev
npm install @babel/eslint-parser --save-dev
npm install eslint-plugin-canonical --save-dev

Configuration

1. Set parser property to babel-eslint.
2. Add plugins section and specify eslint-plugin-canonical as a plugin.
3. Enable rules.

{
  "parser": "@babel/eslint-parser",
  "plugins": [
    "canonical"
  ],
  "rules": {
    "canonical/filename-match-exported": 0,
    "canonical/filename-match-regex": 0,
    "canonical/filename-no-index": 0,
    "canonical/id-match": 0,
    "canonical/no-restricted-strings": 0,
    "canonical/sort-keys": 0
  }
}

Shareable configurations

Recommended

This plugin exports a recommended configuration that enforces Canonical type good practices.

To enable this configuration use the extends property in your .eslintrc config file:

{
  "extends": [
    "plugin:canonical/recommended"
  ],
  "plugins": [
    "canonical"
  ]
}

See ESLint documentation for more information about extending configuration files.

Rules

filename-match-exported

Match the file name against the default exported value in the module. Files that dont have a default export will be ignored. The exports of index.js are matched against their parent directory.

// Considered problem only if the file isn't named foo.js or foo/index.js
export default function foo() {}

// Considered problem only if the file isn't named Foo.js or Foo/index.js
module.exports = class Foo() {}

// Considered problem only if the file isn't named someVariable.js or someVariable/index.js
module.exports = someVariable;

// Never considered a problem
export default { foo: "bar" };

If your filename policy doesn't quite match with your variable naming policy, you can add one or multiple transforms:

"canonical/filename-match-exported": [ 2, "kebab" ]

Now, in your code:

// Considered problem only if file isn't named variable-name.js or variable-name/index.js
export default function variableName;

Available transforms: 'snake', 'kebab', 'camel', and 'pascal' (camel-cased with first letter in upper case).

For multiple transforms simply specify an array like this (null in this case stands for no transform):

"canonical/filename-match-exported": [2, [ null, "kebab", "snake" ] ]

If you prefer to use suffixes for your files (e.g. Foo.react.js for a React component file), you can use a second configuration parameter. It allows you to remove parts of a filename matching a regex pattern before transforming and matching against the export.

"canonical/filename-match-exported": [ 2, null, "\\.react$" ]

Now, in your code:

// Considered problem only if file isn't named variableName.react.js, variableName.js or variableName/index.js
export default function variableName;

If you also want to match exported function calls you can use the third option (a boolean flag).

"canonical/filename-match-exported": [ 2, null, null, true ]

Now, in your code:

// Considered problem only if file isn't named functionName.js or functionName/index.js
export default functionName();

The following patterns are considered problems:

module.exports = exported;
// Message: Filename 'fooBar' must match the exported name 'exported'.

module.exports = class Foo {};
// Message: Filename 'foo' must match the exported name 'Foo'.

module.exports = class Foo { render() { return <span>Test Class</span>; } };
// Message: Filename 'foo' must match the exported name 'Foo'.

module.exports = function foo() {};
// Message: Filename 'bar' must match the exported name 'foo'.

module.exports = function foo() { return <span>Test Fn</span> };
// Message: Filename 'bar' must match the exported name 'foo'.

export default exported;
// Message: Filename 'fooBar' must match the exported name 'exported'.

export default class Foo {};
// Message: Filename 'bar' must match the exported name 'Foo'.

export default class Foo { render() { return <span>Test Class</span>; } };
// Message: Filename 'bar' must match the exported name 'Foo'.

export default function foo() {};
// Message: The directory 'fooBar' must be named 'foo', after the exported value of its index file.

export default function foo() { return <span>Test Fn</span> };
// Message: The directory 'fooBar' must be named 'foo', after the exported value of its index file.

module.exports = exported;
// Message: The directory 'eslint-plugin-canonical' must be named 'exported', after the exported value of its index file.

module.exports = class Foo { render() { return <span>Test Class</span>; } };
// Message: Filename 'Foo.react' must match the exported name 'Foo'.

// Options: ["snake"]
module.exports = variableName;
// Message: Filename 'variableName' must match the exported and transformed name 'variable_name'.

// Options: ["kebab"]
export default variableName;
// Message: Filename 'variableName' must match the exported and transformed name 'variable-name'.

// Options: ["pascal"]
export default variableName;
// Message: Filename 'variableName' must match the exported and transformed name 'VariableName'.

// Options: [[null]]
export default variableName;
// Message: Filename 'VariableName' must match the exported name 'variableName'.

// Options: [["pascal","snake"]]
export default variableName;
// Message: Filename 'variableName' must match any of the exported and transformed names 'VariableName', 'variable_name'.

// Options: [null,"\\.react$"]
export default class Foo { render() { return <span>Test Class</span>; } };
// Message: Filename 'Foo.bar' must match the exported name 'Foo'.

// Options: [null,"\\.react$"]
export default class Foo { render() { return <span>Test Class</span>; } };
// Message: The directory 'Foo.react' must be named 'Foo', after the exported value of its index file.

// Options: [null,null,true]
module.exports = foo();
// Message: Filename 'bar' must match the exported name 'foo'.

The following patterns are not considered problems:

module.exports = function() {};

var foo = 'bar';

export default foo();

module.exports = exported;

module.exports = class Foo {};

module.exports = class Foo { render() { return <span>Test Class</span>; } };

module.exports = function foo() {};

module.exports = foo();

module.exports = function foo() { return <span>Test Fn</span> };

export default exported;

export default class Foo {};

export default class Foo { render() { return <span>Test Class</span>; } };

export default function foo() {};

export default function foo() { return <span>Test Fn</span> };

export default function foo() {};

export default function foo() { return <span>Test Fn</span> };

export default function index() {};

// Options: ["snake"]
module.exports = variableName;

// Options: ["snake"]
module.exports = variableName;

// Options: ["kebab"]
module.exports = variableName;

// Options: ["camel"]
module.exports = variable_name;

// Options: ["snake"]
export default variableName;

// Options: ["kebab"]
export default variableName;

// Options: ["camel"]
export default variable_name;

// Options: ["pascal"]
export default variable_name;

// Options: [["pascal","camel"]]
export default variable_name;

// Options: [["pascal","camel"]]
export default variable_name;

// Options: [null,"\\.react$"]
module.exports = class Foo { render() { return <span>Test Class</span>; } };

// Options: [null,"\\.react$"]
export default class Foo { render() { return <span>Test Class</span>; } };

// Options: [null,null,true]
module.exports = foo();

filename-match-regex

A rule to enforce a certain file naming convention using a regular expression.

The convention can be configured using a regular expression (the default is camelCase.js). Additionally exporting files can be ignored with a second configuration parameter.

"canonical/filename-match-regex": [2, "^[a-z_]+$", true]

With these configuration options, camelCase.js will be reported as an error while snake_case.js will pass. Additionally the files that have a named default export (according to the logic in the match-exported rule) will be ignored. They could be linted with the match-exported rule. Please note that exported function calls are not respected in this case.

The following patterns are considered problems:

var foo = 'bar';
// Message: Filename 'foo_bar.js' does not match the naming convention.

var foo = 'bar';
// Message: Filename 'fooBAR.js' does not match the naming convention.

var foo = 'bar';
// Message: Filename 'fooBar$.js' does not match the naming convention.

// Options: ["^[a-z_]$"]
var foo = 'bar';
// Message: Filename 'fooBar.js' does not match the naming convention.

The following patterns are not considered problems:

var foo = 'bar';

var foo = 'bar';

var foo = 'bar';

// Options: ["^[a-z_]+$"]
var foo = 'bar';

// Options: ["^[a-z_]+$"]
var foo = 'bar';

var foo = 'bar';

// Options: [null,true]
module.exports = foo

// Options: ["^[a-z_]$",true]
module.exports = foo

// Options: ["^[a-z_]+$",true]
module.exports = foo()

filename-no-index

Having a bunch of index.js files can have negative influence on developer experience, e.g. when opening files by name. When enabling this rule. index.js files will always be considered a problem.

The following patterns are considered problems:

var foo = 'bar';
// Message: 'index.js' files are not allowed.

var foo = 'bar';
// Message: 'index.js' files are not allowed.

The following patterns are not considered problems:

var foo = 'bar';

var foo = 'bar';

var foo = 'bar';

var foo = 'bar';

id-match

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

Note: This rule is equivalent to id-match, except for addition of ignoreNamedImports.

This rule requires identifiers in assignments and function definitions to match a specified regular expression.

Options

• "properties": false (default) does not check object properties
• "properties": true requires object literal properties and member expression assignment properties to match the specified regular expression
• "classFields": false (default) does not class field names
• "classFields": true requires class field names to match the specified regular expression
• "onlyDeclarations": false (default) requires all variable names to match the specified regular expression
• "onlyDeclarations": true requires only var, function, and class declarations to match the specified regular expression
• "ignoreDestructuring": false (default) enforces id-match for destructured identifiers
• "ignoreDestructuring": true does not check destructured identifiers
• "ignoreNamedImports": false (default) enforces id-match for named imports
• "ignoreNamedImports": true does not check named imports

The following patterns are considered problems:

// Options: ["^[a-z]+$",{"onlyDeclarations":true}]
var __foo = "Matthieu"
// Message: undefined

// Options: ["^[a-z]+$"]
first_name = "Matthieu"
// Message: undefined

// Options: ["^z"]
first_name = "Matthieu"
// Message: undefined

// Options: ["^[a-z]+(_[A-Z][a-z])*$"]
Last_Name = "Larcher"
// Message: undefined

// Options: ["^[^_]+$",{"properties":true}]
var obj = {key: no_under}
// Message: Identifier 'no_under' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$"]
function no_under21(){}
// Message: undefined

// Options: ["^[^_]+$",{"properties":true}]
obj.no_under22 = function(){};
// Message: undefined

// Options: ["^[^_]+$",{"properties":true}]
no_under23.foo = function(){};
// Message: undefined

// Options: ["^[^_]+$",{"properties":true}]
[no_under24.baz]
// Message: undefined

// Options: ["^[^_]+$",{"properties":true}]
if (foo.bar_baz === boom.bam_pow) { [no_under25.baz] }
// Message: undefined

// Options: ["^[^_]+$",{"properties":true}]
foo.no_under26 = boom.bam_pow
// Message: undefined

// Options: ["^[^_]+$",{"properties":true}]
var foo = { no_under27: boom.bam_pow }
// Message: undefined

// Options: ["^[^_]+$",{"properties":true}]
foo.qux.no_under28 = { bar: boom.bam_pow }
// Message: undefined

// Options: ["^[^_]+$",{"properties":true}]
var o = {no_under29: 1}
// Message: undefined

// Options: ["^[^_]+$",{"properties":true}]
obj.no_under30 = 2;
// Message: undefined

// Options: ["^[^_]+$",{"properties":true}]
var { category_id: category_alias } = query;
// Message: Identifier 'category_alias' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"ignoreDestructuring":true,"properties":true}]
var { category_id: category_alias } = query;
// Message: Identifier 'category_alias' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"ignoreDestructuring":true,"properties":true}]
var { category_id: categoryId, ...other_props } = query;
// Message: Identifier 'other_props' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
var { category_id } = query;
// Message: Identifier 'category_id' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
var { category_id = 1 } = query;
// Message: Identifier 'category_id' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
import no_camelcased from "external-module";
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
import * as no_camelcased from "external-module";
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$"]
export * as no_camelcased from "external-module";
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
import { no_camelcased as no_camel_cased } from "external module";
// Message: Identifier 'no_camel_cased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
import { camelCased as no_camel_cased } from "external module";
// Message: Identifier 'no_camel_cased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
import { camelCased, no_camelcased } from "external-module";
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
import { no_camelcased as camelCased, another_no_camelcased } from "external-module";
// Message: Identifier 'another_no_camelcased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
import camelCased, { no_camelcased } from "external-module";
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
import no_camelcased, { another_no_camelcased as camelCased } from "external-module";
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
function foo({ no_camelcased }) {};
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
function foo({ no_camelcased = 'default value' }) {};
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
const no_camelcased = 0; function foo({ camelcased_value = no_camelcased }) {}
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.
// Message: Identifier 'camelcased_value' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
const { bar: no_camelcased } = foo;
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
function foo({ value_1: my_default }) {}
// Message: Identifier 'my_default' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
function foo({ isCamelcased: no_camelcased }) {};
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
var { foo: bar_baz = 1 } = quz;
// Message: Identifier 'bar_baz' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"properties":true}]
const { no_camelcased = false } = bar;
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$"]
class x { _foo() {} }
// Message: Identifier '_foo' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"classFields":true}]
class x { _foo = 1; }
// Message: Identifier '_foo' does not match the pattern '^[^_]+$'.

// Options: ["^[^_]+$",{"ignoreNamedImports":false}]
import { no_camelcased } from "external-module";
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

The following patterns are not considered problems:

// Options: ["^[a-z]+$",{"onlyDeclarations":true}]
__foo = "Matthieu"

// Options: ["^[a-z]+$"]
firstname = "Matthieu"

// Options: ["[a-z]+"]
first_name = "Matthieu"

// Options: ["^f"]
firstname = "Matthieu"

// Options: ["^[a-z]+(_[A-Z][a-z]+)*$"]
last_Name = "Larcher"

// Options: ["^[a-z]+(_[A-Z][a-z])*$"]
param = "none"

// Options: ["^[^_]+$"]
function noUnder(){}

// Options: ["^[^_]+$"]
no_under()

// Options: ["^[^_]+$"]
foo.no_under2()

// Options: ["^[^_]+$"]
var foo = bar.no_under3;

// Options: ["^[^_]+$"]
var foo = bar.no_under4.something;

// Options: ["^[^_]+$"]
foo.no_under5.qux = bar.no_under6.something;

// Options: ["^[^_]+$"]
if (bar.no_under7) {}

// Options: ["^[^_]+$"]
var obj = { key: foo.no_under8 };

// Options: ["^[^_]+$"]
var arr = [foo.no_under9];

// Options: ["^[^_]+$"]
[foo.no_under10]

// Options: ["^[^_]+$"]
var arr = [foo.no_under11.qux];

// Options: ["^[^_]+$"]
[foo.no_under12.nesting]

// Options: ["^[^_]+$"]
if (foo.no_under13 === boom.no_under14) { [foo.no_under15] }

// Options: ["^[a-z$]+([A-Z][a-z]+)*$"]
var myArray = new Array(); var myDate = new Date();

// Options: ["^[^_]+$"]
var x = obj._foo;

// Options: ["^[^_]+$",{"onlyDeclarations":true,"properties":true}]
var obj = {key: no_under}

// Options: ["^[^_]+$",{"properties":true}]
var {key_no_under: key} = {}

// Options: ["^[^_]+$",{"ignoreDestructuring":true,"properties":true}]
var { category_id } = query;

// Options: ["^[^_]+$",{"ignoreDestructuring":true,"properties":true}]
var { category_id: category_id } = query;

// Options: ["^[^_]+$",{"ignoreDestructuring":true,"properties":true}]
var { category_id = 1 } = query;

// Options: ["^[^_]+$",{"properties":true}]
var o = {key: 1}

// Options: ["^[^_]+$",{"properties":false}]
var o = {no_under16: 1}

// Options: ["^[^_]+$",{"properties":false}]
obj.no_under17 = 2;

// Options: ["^[^_]+$",{"properties":false}]
var obj = {
 no_under18: 1 
};
 obj.no_under19 = 2;

// Options: ["^[^_]+$",{"properties":false}]
obj.no_under20 = function(){};

// Options: ["^[^_]+$",{"properties":false}]
var x = obj._foo2;

// Options: ["^[^_]+$"]
class x { foo() {} }

// Options: ["^[^_]+$"]
class x { #foo() {} }

// Options: ["^[^_]+$",{"ignoreNamedImports":true}]
import { no_camelcased } from "external-module";
// Message: Identifier 'no_camelcased' does not match the pattern '^[^_]+$'.

no-restricted-strings

Disallow specified strings.

The following patterns are considered problems:

// Options: [["bar"]]
var foo = "bar"
// Message: Disallowed string: 'bar'.

// Options: [["bar"]]
const foo = `bar ${baz}`;
// Message: Disallowed string in template: 'bar'.

The following patterns are not considered problems:

const foo = "bar";

Options

The 1st option is an array of strings that cannot be contained in the codebase.

sort-keys

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

Note: This rule is equivalent to sort-keys, except that it is fixable.

This rule requires identifiers in assignments and function definitions to match a specified regular expression.

Options

The 1st option is "asc" or "desc".

• "asc" (default) - enforce properties to be in ascending order.
• "desc" - enforce properties to be in descending order.

The 2nd option is an object which has 3 properties.

• caseSensitive - if true, enforce properties to be in case-sensitive order. Default is true.
• minKeys - Specifies the minimum number of keys that an object should have in order for the object's unsorted keys to produce an error. Default is 2, which means by default all objects with unsorted keys will result in lint errors.
• natural - if true, enforce properties to be in natural order. Default is false. Natural Order compares strings containing combination of letters and numbers in the way a human being would sort. It basically sorts numerically, instead of sorting alphabetically. So the number 10 comes after the number 3 in Natural Sorting.

The following patterns are considered problems:

var obj = {
// comment
// comment 2
a:1,
_:2,
b:3
}
// Message: undefined

var obj = {
/* comment
 comment 2 */
a:1,
_:2,
b:3
}
// Message: undefined

var obj = {a:1, _:2, b:3} // default
// Message: undefined

var obj = {a:1, c:2, b:3}
// Message: undefined

var obj = {b_:1, a:2, b:3}
// Message: undefined

var obj = {b_:1, c:2, C:3}
// Message: undefined

var obj = {$:1, _:2, A:3, a:4}
// Message: undefined

var obj = {1:1, 2:4, A:3, '11':2}
// Message: undefined

var obj = {'#':1, À:3, 'Z':2, è:4}
// Message: undefined

var obj = {...z, c:1, b:1}
// Message: undefined

var obj = {...z, ...c, d:4, b:1, ...y, ...f, e:2, a:1}
// Message: undefined
// Message: undefined

var obj = {c:1, b:1, ...a}
// Message: undefined

var obj = {...z, ...a, c:1, b:1}
// Message: undefined

var obj = {...z, b:1, a:1, ...d, ...c}
// Message: undefined

// Options: ["desc"]
var obj = {...z, a:2, b:0, ...x, ...c}
// Message: undefined

// Options: ["desc"]
var obj = {...z, a:2, b:0, ...x}
// Message: undefined

// Options: ["desc"]
var obj = {...z, '':1, a:2}
// Message: undefined

var obj = {a:1, [b+c]:2, '':3}
// Message: undefined

// Options: ["desc"]
var obj = {'':1, [b+c]:2, a:3}
// Message: undefined

// Options: ["desc"]
var obj = {b:1, [f()]:2, '':3, a:4}
// Message: undefined

var obj = {a:1, b:3, [a]: -1, c:2}
// Message: undefined

var obj = {a:1, c:{y:1, x:1}, b:1}
// Message: undefined
// Message: undefined

// Options: ["asc"]
var obj = {a:1, _:2, b:3} // asc
// Message: undefined

// Options: ["asc"]
var obj = {a:1, c:2, b:3}
// Message: undefined

// Options: ["asc"]
var obj = {b_:1, a:2, b:3}
// Message: undefined

// Options: ["asc"]
var obj = {b_:1, c:2, C:3}
// Message: undefined

// Options: ["asc"]
var obj = {$:1, _:2, A:3, a:4}
// Message: undefined

// Options: ["asc"]
var obj = {1:1, 2:4, A:3, '11':2}
// Message: undefined

// Options: ["asc"]
var obj = {'#':1, À:3, 'Z':2, è:4}
// Message: undefined

// Options: ["asc",{"caseSensitive":false}]
var obj = {a:1, _:2, b:3} // asc, insensitive
// Message: undefined

// Options: ["asc",{"caseSensitive":false}]
var obj = {a:1, c:2, b:3}
// Message: undefined

// Options: ["asc",{"caseSensitive":false}]
var obj = {b_:1, a:2, b:3}
// Message: undefined

// Options: ["asc",{"caseSensitive":false}]
var obj = {$:1, A:3, _:2, a:4}
// Message: undefined

// Options: ["asc",{"caseSensitive":false}]
var obj = {1:1, 2:4, A:3, '11':2}
// Message: undefined

// Options: ["asc",{"caseSensitive":false}]
var obj = {'#':1, À:3, 'Z':2, è:4}
// Message: undefined

// Options: ["asc",{"natural":true}]
var obj = {a:1, _:2, b:3} // asc, natural
// Message: undefined

// Options: ["asc",{"natural":true}]
var obj = {a:1, c:2, b:3}
// Message: undefined

// Options: ["asc",{"natural":true}]
var obj = {b_:1, a:2, b:3}
// Message: undefined

// Options: ["asc",{"natural":true}]
var obj = {b_:1, c:2, C:3}
// Message: undefined

// Options: ["asc",{"natural":true}]
var obj = {$:1, A:3, _:2, a:4}
// Message: undefined

// Options: ["asc",{"natural":true}]
var obj = {1:1, 2:4, A:3, '11':2}
// Message: undefined

// Options: ["asc",{"natural":true}]
var obj = {'#':1, À:3, 'Z':2, è:4}
// Message: undefined

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {a:1, _:2, b:3} // asc, natural, insensitive
// Message: undefined

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {a:1, c:2, b:3}
// Message: undefined

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {b_:1, a:2, b:3}
// Message: undefined

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {$:1, A:3, _:2, a:4}
// Message: undefined

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {1:1, '11':2, 2:4, A:3}
// Message: undefined

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {'#':1, À:3, 'Z':2, è:4}
// Message: undefined

// Options: ["desc"]
var obj = {a:1, _:2, b:3} // desc
// Message: undefined

// Options: ["desc"]
var obj = {a:1, c:2, b:3}
// Message: undefined

// Options: ["desc"]
var obj = {b_:1, a:2, b:3}
// Message: undefined

// Options: ["desc"]
var obj = {b_:1, c:2, C:3}
// Message: undefined

// Options: ["desc"]
var obj = {$:1, _:2, A:3, a:4}
// Message: undefined
// Message: undefined

// Options: ["desc"]
var obj = {1:1, 2:4, A:3, '11':2}
// Message: undefined
// Message: undefined

// Options: ["desc"]
var obj = {'#':1, À:3, 'Z':2, è:4}
// Message: undefined
// Message: undefined

// Options: ["desc",{"caseSensitive":false}]
var obj = {a:1, _:2, b:3} // desc, insensitive
// Message: undefined

// Options: ["desc",{"caseSensitive":false}]
var obj = {a:1, c:2, b:3}
// Message: undefined

// Options: ["desc",{"caseSensitive":false}]
var obj = {b_:1, a:2, b:3}
// Message: undefined

// Options: ["desc",{"caseSensitive":false}]
var obj = {b_:1, c:2, C:3}
// Message: undefined

// Options: ["desc",{"caseSensitive":false}]
var obj = {$:1, _:2, A:3, a:4}
// Message: undefined
// Message: undefined

// Options: ["desc",{"caseSensitive":false}]
var obj = {1:1, 2:4, A:3, '11':2}
// Message: undefined
// Message: undefined

// Options: ["desc",{"caseSensitive":false}]
var obj = {'#':1, À:3, 'Z':2, è:4}
// Message: undefined
// Message: undefined

// Options: ["desc",{"natural":true}]
var obj = {a:1, _:2, b:3} // desc, natural
// Message: undefined

// Options: ["desc",{"natural":true}]
var obj = {a:1, c:2, b:3}
// Message: undefined

// Options: ["desc",{"natural":true}]
var obj = {b_:1, a:2, b:3}
// Message: undefined

// Options: ["desc",{"natural":true}]
var obj = {b_:1, c:2, C:3}
// Message: undefined

// Options: ["desc",{"natural":true}]
var obj = {$:1, _:2, A:3, a:4}
// Message: undefined
// Message: undefined
// Message: undefined

// Options: ["desc",{"natural":true}]
var obj = {1:1, 2:4, A:3, '11':2}
// Message: undefined
// Message: undefined

// Options: ["desc",{"natural":true}]
var obj = {'#':1, À:3, 'Z':2, è:4}
// Message: undefined
// Message: undefined

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {a:1, _:2, b:3} // desc, natural, insensitive
// Message: undefined

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {a:1, c:2, b:3}
// Message: undefined

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {b_:1, a:2, b:3}
// Message: undefined

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {b_:1, c:2, C:3}
// Message: undefined

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {$:1, _:2, A:3, a:4}
// Message: undefined
// Message: undefined

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {1:1, 2:4, '11':2, A:3}
// Message: undefined
// Message: undefined
// Message: undefined

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {'#':1, À:3, 'Z':2, è:4}
// Message: undefined
// Message: undefined

The following patterns are not considered problems:

// Options: []
var obj = {_:2, a:1, b:3} // default

// Options: []
var obj = {a:1, b:3, c:2}

// Options: []
var obj = {a:2, b:3, b_:1}

// Options: []
var obj = {C:3, b_:1, c:2}

// Options: []
var obj = {$:1, A:3, _:2, a:4}

// Options: []
var obj = {1:1, '11':2, 2:4, A:3}

// Options: []
var obj = {'#':1, 'Z':2, À:3, è:4}

// Options: []
var obj = {a:1, b:3, [a + b]: -1, c:2}

// Options: []
var obj = {'':1, [f()]:2, a:3}

// Options: ["desc"]
var obj = {a:1, [b++]:2, '':3}

// Options: []
var obj = {a:1, ...z, b:1}

// Options: []
var obj = {b:1, ...z, a:1}

// Options: []
var obj = {...a, b:1, ...c, d:1}

// Options: []
var obj = {...a, b:1, ...d, ...c, e:2, z:5}

// Options: []
var obj = {b:1, ...c, ...d, e:2}

// Options: []
var obj = {a:1, ...z, '':2}

// Options: ["desc"]
var obj = {'':1, ...z, 'a':2}

// Options: []
var obj = {...z, a:1, b:1}

// Options: []
var obj = {...z, ...c, a:1, b:1}

// Options: []
var obj = {a:1, b:1, ...z}

// Options: ["desc"]
var obj = {...z, ...x, a:1, ...c, ...d, f:5, e:4}

// Options: []
function fn(...args) { return [...args].length; }

// Options: []
function g() {}; function f(...args) { return g(...args); }

// Options: []
let {a, b} = {}

// Options: []
var obj = {a:1, b:{x:1, y:1}, c:1}

// Options: ["asc"]
var obj = {_:2, a:1, b:3} // asc

// Options: ["asc"]
var obj = {a:1, b:3, c:2}

// Options: ["asc"]
var obj = {a:2, b:3, b_:1}

// Options: ["asc"]
var obj = {C:3, b_:1, c:2}

// Options: ["asc"]
var obj = {$:1, A:3, _:2, a:4}

// Options: ["asc"]
var obj = {1:1, '11':2, 2:4, A:3}

// Options: ["asc"]
var obj = {'#':1, 'Z':2, À:3, è:4}

// Options: ["asc",{"caseSensitive":false}]
var obj = {_:2, a:1, b:3} // asc, insensitive

// Options: ["asc",{"caseSensitive":false}]
var obj = {a:1, b:3, c:2}

// Options: ["asc",{"caseSensitive":false}]
var obj = {a:2, b:3, b_:1}

// Options: ["asc",{"caseSensitive":false}]
var obj = {b_:1, C:3, c:2}

// Options: ["asc",{"caseSensitive":false}]
var obj = {b_:1, c:3, C:2}

// Options: ["asc",{"caseSensitive":false}]
var obj = {$:1, _:2, A:3, a:4}

// Options: ["asc",{"caseSensitive":false}]
var obj = {1:1, '11':2, 2:4, A:3}

// Options: ["asc",{"caseSensitive":false}]
var obj = {'#':1, 'Z':2, À:3, è:4}

// Options: ["asc",{"natural":true}]
var obj = {_:2, a:1, b:3} // asc, natural

// Options: ["asc",{"natural":true}]
var obj = {a:1, b:3, c:2}

// Options: ["asc",{"natural":true}]
var obj = {a:2, b:3, b_:1}

// Options: ["asc",{"natural":true}]
var obj = {C:3, b_:1, c:2}

// Options: ["asc",{"natural":true}]
var obj = {$:1, _:2, A:3, a:4}

// Options: ["asc",{"natural":true}]
var obj = {1:1, 2:4, '11':2, A:3}

// Options: ["asc",{"natural":true}]
var obj = {'#':1, 'Z':2, À:3, è:4}

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {_:2, a:1, b:3} // asc, natural, insensitive

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {a:1, b:3, c:2}

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {a:2, b:3, b_:1}

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {b_:1, C:3, c:2}

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {b_:1, c:3, C:2}

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {$:1, _:2, A:3, a:4}

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {1:1, 2:4, '11':2, A:3}

// Options: ["asc",{"caseSensitive":false,"natural":true}]
var obj = {'#':1, 'Z':2, À:3, è:4}

// Options: ["desc"]
var obj = {b:3, a:1, _:2} // desc

// Options: ["desc"]
var obj = {c:2, b:3, a:1}

// Options: ["desc"]
var obj = {b_:1, b:3, a:2}

// Options: ["desc"]
var obj = {c:2, b_:1, C:3}

// Options: ["desc"]
var obj = {a:4, _:2, A:3, $:1}

// Options: ["desc"]
var obj = {A:3, 2:4, '11':2, 1:1}

// Options: ["desc"]
var obj = {è:4, À:3, 'Z':2, '#':1}

// Options: ["desc",{"caseSensitive":false}]
var obj = {b:3, a:1, _:2} // desc, insensitive

// Options: ["desc",{"caseSensitive":false}]
var obj = {c:2, b:3, a:1}

// Options: ["desc",{"caseSensitive":false}]
var obj = {b_:1, b:3, a:2}

// Options: ["desc",{"caseSensitive":false}]
var obj = {c:2, C:3, b_:1}

// Options: ["desc",{"caseSensitive":false}]
var obj = {C:2, c:3, b_:1}

// Options: ["desc",{"caseSensitive":false}]
var obj = {a:4, A:3, _:2, $:1}

// Options: ["desc",{"caseSensitive":false}]
var obj = {A:3, 2:4, '11':2, 1:1}

// Options: ["desc",{"caseSensitive":false}]
var obj = {è:4, À:3, 'Z':2, '#':1}

// Options: ["desc",{"natural":true}]
var obj = {b:3, a:1, _:2} // desc, natural

// Options: ["desc",{"natural":true}]
var obj = {c:2, b:3, a:1}

// Options: ["desc",{"natural":true}]
var obj = {b_:1, b:3, a:2}

// Options: ["desc",{"natural":true}]
var obj = {c:2, b_:1, C:3}

// Options: ["desc",{"natural":true}]
var obj = {a:4, A:3, _:2, $:1}

// Options: ["desc",{"natural":true}]
var obj = {A:3, '11':2, 2:4, 1:1}

// Options: ["desc",{"natural":true}]
var obj = {è:4, À:3, 'Z':2, '#':1}

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {b:3, a:1, _:2} // desc, natural, insensitive

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {c:2, b:3, a:1}

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {b_:1, b:3, a:2}

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {c:2, C:3, b_:1}

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {C:2, c:3, b_:1}

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {a:4, A:3, _:2, $:1}

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {A:3, '11':2, 2:4, 1:1}

// Options: ["desc",{"caseSensitive":false,"natural":true}]
var obj = {è:4, À:3, 'Z':2, '#':1}