Perfectionist

sort-heritage-clauses

Enforce sorted heritage clauses.

This rule detects instances where heritage clauses are not sorted and raises linting errors, encouraging developers to arrange elements in the desired order.

Try it out

Options

This rule accepts an options object with the following properties:

type

default: 'alphabetical'

Specifies the sorting method.

  • 'alphabetical' — Sort items alphabetically (e.g., “a” < “b” < “c”) using localeCompare.
  • 'natural' — Sort items in a natural order (e.g., “item2” < “item10”).
  • 'line-length' — Sort items by the length of the code line (shorter lines first).
  • 'custom' — Sort items using the alphabet entered in the alphabet option.

order

default: 'asc'

Determines whether the sorted items should be in ascending or descending order.

  • 'asc' — Sort items in ascending order (A to Z, 1 to 9).
  • 'desc' — Sort items in descending order (Z to A, 9 to 1).

alphabet

default: ''

Only used when the type option is set to 'custom'. Specifies the custom alphabet to use when sorting.

Use the Alphabet utility class from eslint-plugin-perfectionist/alphabet to quickly generate a custom alphabet.

Example: 0123456789abcdef...

ignoreCase

default: true

Controls whether sorting should be case-sensitive or not.

  • true — Ignore case when sorting alphabetically or naturally (e.g., “A” and “a” are the same).
  • false — Consider case when sorting (e.g., “a” comes before “A”).

specialCharacters

default: keep

Controls whether special characters should be trimmed, removed or kept before sorting.

  • 'keep' — Keep special characters when sorting (e.g., “_a” comes before “a”).
  • 'trim' — Trim special characters when sorting alphabetically or naturally (e.g., “_a” and “a” are the same).
  • 'remove' — Remove special characters when sorting (e.g., “/a/b” and “ab” are the same).

locales

default: 'en-US'

Specifies the sorting locales. See String.prototype.localeCompare() - locales.

  • string — A BCP 47 language tag (e.g. 'en', 'en-US', 'zh-CN').
  • string[] — An array of BCP 47 language tags.

groups

type: Array<string | string[]>

default: []

Allows you to specify a list of heritage clause groups for sorting.

Predefined groups:

  • 'unknown' — Heritage Clauses that don’t fit into any group specified in the groups option.

If the unknown group is not specified in the groups option, it will automatically be added to the end of the list.

Each heritage clause will be assigned a single group specified in the groups option (or the unknown group if no match is found). The order of items in the groups option determines how groups are ordered.

Within a given group, members will be sorted according to the type, order, ignoreCase, etc. options.

Individual groups can be combined together by placing them in an array. The order of groups in that array does not matter. All members of the groups in the array will be sorted together as if they were part of a single group.

customGroups

type: { [groupName: string]: string | string[] }

default: {}

You can define your own groups and use regex to match specific heritage clauses.

Each key of customGroups represents a group name which you can then use in the groups option. The value for each key can either be of type:

  • string — A heritage clause’s name matching the value will be marked as part of the group referenced by the key.
  • string[] — A heritage clause’s name matching any of the values of the array will be marked as part of the group referenced by the key. The order of values in the array does not matter.

Custom group matching takes precedence over predefined group matching.

Example:

Put the WithId clause before anything else:

interface Interface extends WithId, Logged, StartupService {
 // ...
}

groups and customGroups configuration:

 {
   groups: [
     'withIdInterface',
     'unknown'
   ],
+  customGroups: {              
+    withIdInterface: '^WithId'
+  }                            
 }

Usage

Version

This rule was introduced in v4.0.0.

Resources

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