.eslintrc

{
    // This file is an opinionated eslint configuration. In terms of number of
    // rules specified in this file, it is a reasonably detailed/specific
    // configuration. For more information for getting started with eslint, see
    // here: https://eslint.org/docs/latest/use/getting-started. For more
    // information specifically on configuring eslint with a .eslintrc, see
    // here: https://eslint.org/docs/latest/use/configure.

    // Language option configuration, for more information, see here: 
    // https://eslint.org/docs/latest/use/configure/language-options#specifying-environments.
    "env": {
        "browser": true,
        "es2022": true,
        "node": true
    },

    // Default option set provided by eslint, which the rules object below 
    // either add to or overwrite.
    "extends": "eslint:recommended",

    // Specify language options which should be supported, most notably node
    // modules instead of commonjs. For more information, see here:
    // https://eslint.org/docs/latest/use/configure/language-options#specifying-parser-options.
    "parserOptions": {
        "ecmaVersion": "latest",
        "sourceType": "module"
    },

    // Specify plugins used by this configuration, for more information, see
    // here: https://eslint.org/docs/latest/use/configure/plugins.
    "plugins": [
        "regex",
        "eslint-comments"
    ],

    // Rules which add to or overwrite the existing default rule set implied by
    // the "extends" field. For more information on rule configuration, see
    // here: https://eslint.org/docs/latest/rules. For more information on any
    // rule set below, see https://eslint.org/docs/latest/rules/<rule-name>.
    // Note that not ALL rules are explicitly set/unset below. Use of ESLint
    // warnings, which may often be ignored, is generally avoided in favour of
    // throwing an error for any incorrect formatting.
    "rules": {
        // Plugin-specific eslint configurations.

        // Regex plugin configuration used for ensuring that specific patterns
        // are/are not matched in any given script. For more information on
        // configuration, see here: https://github.com/gmullerb/eslint-plugin-regex.

        // Invalid regex configuration - i.e. patterns which are not valid in
        // any script. Plugin provides replacement method for regex/invalid
        // rules to automatically resolve a given issue. As such these patterns
        // are preferred over the regex/required patterns.
        "regex/invalid": ["error", [
            // Ensure that each file starts with the required header, including
            // license text, jsdoc file description, and @ts-check or
            // @ts-nocheck directive (in listed order). Note that no rules are
            // included to check for/prevent duplicate header elements
            // elsewhere in a script, although these should be very obvious to
            // spot any time someone is working on a given script.
            {
                "id": "noMissingScriptHeader",
                "regex": "(?<!.|\n)(?!\/\/ Copyright \\(c\\) \\d{4} .*\\. All rights reserved\\.\n\/\/\n\/\/ This source code file is licensed under the terms of the MIT license, a copy\n\/\/ of which may be found in the LICENSE\\.md file in the root of this repository\\.\n\/\/\n\/\/ For a template copy of the license see one of the following 3rd party sites:\n\/\/ {6}- <https:\/\/opensource\\.org\/licenses\/MIT>\n\/\/ {6}- <https:\/\/choosealicense\\.com\/licenses\/mit>\n\/\/ {6}- <https:\/\/spdx\\.org\/licenses\/MIT>\n\n\/\\*\\*\\s*\n([^\\*]|(\\*(?!\/)))*\\s*\\*\\s*@file\\s.*\n([^\\*]|(\\*(?!(\/)|(\\s*@))))*(\\s*\\*\\s*@author\\s.*\n)+\\s*\\*\/\n\n\/\/ (@ts-check|@ts-nocheck)(\n| .*\n)\n)",
                "message": "Script must start with license information, file description, and @ts-check or @ts-nocheck directive.",
                "replacement": {
                    // Insert placeholder header at start of file.
                    "function": "return `// Copyright (c) <INSERT_YEAR_HERE> <INSERT_OWNER_HERE>. All rights reserved.\n//\n// This source code file is licensed under the terms of the MIT license, a copy\n// of which may be found in the LICENSE.md file in the root of this repository.\n//\n// For a template copy of the license see one of the following 3rd party sites:\n//      - <https://opensource.org/licenses/MIT>\n//      - <https://choosealicense.com/licenses/mit>\n//      - <https://spdx.org/licenses/MIT>\n\n/**\n * @file <INSERT_FILE_DESCRIPTION_HERE>\n * @author <INSERT_AUTHOR_HERE>\n */\n\n// @ts-check\n\n`"
                }
            },

            // Ensure that all placeholder header details have been populated
            // when the header has been added using the regex/invalid
            // replacement function.
            {
                "id": "noMissingHeaderDetails",
                "regex": "(?<=\/\/.*|\/\\*\\*.*\n([^\\*]|(\\*(?!\/)))*\\s*\\*.*)<INSERT_[_A-Z]*_HERE>",
                "message": "All header details must be populated."
            },

            // Ensure that no invalid block tags are used in a scripts (mainly
            // for enforcing correct block tags when using multiple import
            // blocks).
            {
                "id": "noInvalidBlockTags",
                "regex": "(?<=\/\/ )@@(?!((no-)?(body|exports|imports)|imports(-(node|dependencies|utils|package|module|submodule|types)))\\s)",
                "message": "Invalid @@<block> block tags not permitted. Remove block tag, or use a valid tag.",
                "replacement": {
                    // Remove @@ in front of matched invalid tag.
                    "function": "return ``"
                }
            },

            // Ensure that no block tag has a description (i.e. a newline
            // character immediately follows the end of the tag).
            {
                "id": "noBlockTagDescriptions",
                "regex": "(?<=\/\/ @@[-a-z]*) .*",
                "message": "Block tag descriptions are not permitted.",
                "replacement": {
                    // Remove any matched block tag description.
                    "function": "return ``"
                }
            },

            // Ensure that every block tag is preceded by a blank line. New
            // lines AFTER block tags at the end of a file are enforced by
            // the eslint "eol-last" setting.
            {
                "id": "noBlockTagPreviousLine",
                "regex": "(?<!\n\n)\/\/ @@.*",
                "message": "Block tags must be preceded by a blank line.",
                "replacement": {
                    // Insert extra newline before matched tag.
                    "function": "return `\n${text}`"
                }
            },

            // Ensure that any block with the "no-" prefix has no content
            // contained within it before the start of the next block.
            {
                "id": "noUsedEmptyBlocks",
                "regex": "(?<=\/\/ @@)no-.*(?=\n)(?!\n*(\/\/ @@.*|$(?!\n)))",
                "message": "Cannot use @@no-<block> to mark a non-empty block, use @@<block> instead.",
                "replacement": {
                    // Remove "no-" prefix from matched tag.
                    "function": "return `${text.replace('no-', '')}`"
                }
            },

            // Ensure that any block without the "no-" prefix has some content
            // contained within it before the start of the next block.
            {
                "id": "noUnusedBlocks",
                "regex": "(?<=\/\/ @@)[^no-].*(?=\n*(\/\/ @@.*|$(?!\n)))",
                "message": "Cannot use @@<block> to mark an empty block, use @@no-<block> instead.",
                "replacement": {
                    // Add "no-" prefix tp matched tag.
                    "function": "return `no-${text}`"
                }
            },

            // Ensure that body or export blocks do not appear more than once
            // in a given script.
            {
                "id": "noDuplicateUniqueBlocks",
                "regex": "(?<=\/\/ @@(no-)?body(.*\n)*)\/\/ @@(no-)?body|(?<=\/\/ @@(no-)?exports(.*\n)*)\/\/ @@(no-)?exports",
                "message": "Unique blocks @@body and @@export cannot appear more than once in a script.",
                "replacement": {
                    // Remove duplicate matched tag.
                    "function": "return ``"
                }
            },

            // Ensure that every script has one or more import block(s), a
            // body block, and and export block. Additionally ensures that
            // these blocks appear in the correct order.
            {
                "id": "noMissingBlocks",
                "regex": "(?<!.|\n)(?!(.*\n)*\/\/ @@((no-)?imports|imports-[a-z]*)\\s(.*\n)*\/\/ @@(no-)?body\\s(.*\n)*\/\/ @@(no-)?exports\\s)",
                "message": "One or more @@<block> tags missing, or blocks are in incorrect order."
            }
        ]],

        // No configuration for regex/required since absence of a given pattern
        // causes an error which highlights the whole file, which can be a
        // little frustrating. Additionally, the regex/required patterns cannot
        // be automatically fixed with the replacement option.

        // Plugin configuration for the eslint-comments plugin, mainly for
        // ensuring that there are no unused, unrestricted or unclosed eslint
        // directives. For more information, please see the plugin page here:
        // https://mysticatea.github.io/eslint-plugin-eslint-comments/.

        // Best practice rules for eslint-comments plugin.
        "eslint-comments/disable-enable-pair": "error",
        "eslint-comments/no-aggregating-enable": "off",
        "eslint-comments/no-duplicate-disable": "error",
        "eslint-comments/no-unlimited-disable": "error",
        "eslint-comments/no-unused-disable": "error",
        "eslint-comments/no-unused-enable": "error",

        // Stylistic suggestions for eslint-comments plugin.
        "eslint-comments/no-restricted-disable": "off",
        "eslint-comments/no-use": "off",
        "eslint-comments/require-description": "error",

        // Eslint "problems" relating to possible logic errors in code. Most
        // rules turned on by default, the following configuration turns off
        // or changes inconvenient default settings. For more information, see
        // here: https://eslint.org/docs/latest/rules/#possible-problems.
        "no-control-regex": "off",
        "no-duplicate-imports": "error",
        "no-ex-assign": "off",
        "no-unused-private-class-members": "error",

        // Eslint "suggestions" relating to alternate ways of organising code
        // which will not give rise to logical errors if not followed, but may
        // be preferable for reducing unnecessary blocks, or enforcing naming
        // conventions etc. Most rules in this category are disabled by
        // default, and this configuration only enables a selection. For more
        // information on all available rules in this category, see here:
        // https://eslint.org/docs/latest/rules/#suggestions.
        "curly": ["error", "all"],
        "default-case": ["error", {
            "commentPattern": "^@no-default"
        }],
        "default-case-last": "error",
        "default-param-last": "error",
        "eqeqeq": "error",
        "func-style": ["error", "declaration", {
            "allowArrowFunctions": true
        }],
        "grouped-accessor-pairs": "error",
        "guard-for-in": "off",
        "id-denylist": ["error", "err", "e", "ev", "cb"],
        "id-match": ["error", "(^[A-Z]?[a-z0-9]*([A-Z][a-z0-9]*)*$)|(^([A-Z0-9]+_?)*$)", {
            "properties": false,
            "classFields": false,
            "onlyDeclarations": true,
            "ignoreDestructuring": true
        }],
        "multiline-comment-style": ["error", "separate-lines"],
        "new-cap": ["error", {
            "newIsCap": true,
            "capIsNew": true,
            "capIsNewExceptions": ["Array"]
        }],
        "no-else-return": "error",
        "no-extra-label": "error",
        "no-label-var": "error",
        "no-lone-blocks": "error",
        "no-useless-return": "error",
        "no-var": "error",
        "prefer-const": "error",
        "spaced-comment": ["error", "always"],
        "yoda": "error",

        // Eslint "layout" rules which have no impact on how the code runs, and
        // only relate to how the code appears in the editor. The majority of
        // these rules are turned off by default, and this configuration sets
        // ALL rules in this category. If the rule should remain off, this
        // configuration explicitly sets it to off below. For more information,
        // see here: https://eslint.org/docs/latest/rules/#layout--formatting.
        "array-bracket-newline": ["error", "consistent"],
        "array-bracket-spacing": ["error", "never"],
        "array-element-newline": ["error", "consistent"],
        "arrow-parens": ["error", "as-needed"],
        "arrow-spacing": ["error", {
            "before": true,
            "after": true
        }],
        "block-spacing": ["error", "always"],
        "brace-style": ["error", "stroustrup", {
            "allowSingleLine": true
        }],
        "comma-dangle": ["error", "only-multiline"],
        "comma-spacing": ["error", {
            "before": false,
            "after": true
        }],
        "comma-style": ["error", "last"],
        "computed-property-spacing": ["error", "never", {
            "enforceForClassMembers": true
        }],
        "dot-location": ["error", "property"],
        "eol-last": ["error", "always"],
        "func-call-spacing": ["error", "never"],
        "function-call-argument-newline": ["error", "consistent"],
        "function-paren-newline": ["error", "consistent"],
        "generator-star-spacing": ["error", {
            "before": false,
            "after": true
        }],
        "implicit-arrow-linebreak": ["error", "beside"],
        "indent": ["error", 4, {
            "ignoredNodes": ["ConditionalExpression"],
            "SwitchCase": 1
        }],
        "jsx-quotes": ["error", "prefer-double"],
        "key-spacing": ["error", {
            "beforeColon": false,
            "afterColon": true,
            "mode": "strict"
        }],
        "keyword-spacing": ["error", {
            "before": true,
            "after": true
        }],
        "line-comment-position": ["off"],
        "linebreak-style": ["error", "unix"],
        "lines-around-comment": ["off"],
        "lines-between-class-members": ["error", {
            "enforce": [
                { "blankLine": "always", "prev": "method", "next": "method" },
                { "blankLine": "always", "prev": "method", "next": "field" },
                { "blankLine": "always", "prev": "field", "next": "method" },
                { "blankLine": "never", "prev": "field", "next": "field" }
            ]
        }],
        "max-len": ["error", {
            "code": 80,
            "tabWidth": 4,
            "comments": 80,
            "ignorePattern": "^.*@no-wrap$",
            "ignoreUrls": true,
            "ignoreStrings": true,
            "ignoreTemplateLiterals": true,
            "ignoreRegExpLiterals": true
        }],
        "new-parens": ["error", "always"],
        "newline-per-chained-call": ["error", {
            "ignoreChainWithDepth": 3
        }],
        "no-extra-parens": ["off"],
        "no-mixed-spaces-and-tabs": "error",
        "no-multi-spaces": ["error", {
            "ignoreEOLComments": false,
            "exceptions": { "Property": false } 
        }],
        "no-multiple-empty-lines": ["error", {
            "max": 1,
            "maxEOF": 1,
            "maxBOF": 1
        }],
        "no-tabs": "error",
        "no-trailing-spaces": ["error", {
            "skipBlankLines": false,
            "ignoreComments": false
        }],
        "no-whitespace-before-property": "error",
        "nonblock-statement-body-position": ["error", "beside"],
        "object-curly-newline": ["error", {
            "consistent": true
        }],
        "object-curly-spacing": ["error", "always"],
        "operator-linebreak": ["error", "after", {
            "overrides": { 
                ":": "before",
                "?": "before"
            }
        }],
        "padded-blocks": ["error", "never"],
        "padding-line-between-statements": ["off"],
        "quotes": ["error", "double"],
        "rest-spread-spacing": ["error", "never"],
        "semi": ["error", "never"],
        "semi-spacing": ["error", {
            "before": false,
            "after": true
        }],
        "semi-style": ["error", "last"],
        "space-before-blocks": ["error", "always"],
        "space-before-function-paren": ["error", {
            "anonymous": "always",
            "named": "never",
            "asyncArrow": "always"
        }],
        "space-in-parens": ["error", "never"],
        "space-infix-ops": "error",
        "space-unary-ops": ["error", {
            "words": true,
            "nonwords": true,
            "overrides": {
                "++": false,
                "--": false,
                "!": false,
                "~": false
            }
        }],
        "switch-colon-spacing": ["error", {
            "before": false,
            "after": true
        }],
        "template-curly-spacing": ["error", "never"],
        "template-tag-spacing": ["error", "never"],
        "unicode-bom": ["error", "never"],
        "wrap-iife": ["error", "inside"],
        "yield-star-spacing": ["error", {
            "before": false,
            "after": true
        }]
    }
}