.eslintrc.yaml

root: true

parser: '@typescript-eslint/parser'

parserOptions:
    project: 
        - ./tsconfig.json

extends:
    - eslint:recommended
    - airbnb-base
    - plugin:@typescript-eslint/recommended
    - plugin:@typescript-eslint/recommended-requiring-type-checking

plugins: ["@typescript-eslint"]

settings:
    import/resolver:
        node:
            extensions:
                - .js
                - .jsx
                - .ts
                - .tsx
                - .d.ts

env:
    browser: true
    node: true
    es6: true
    jest: true

globals:
    cc: false
    wx: false
    Editor: false
    _Scene: false
    _ccsg: false

rules:

    # https://eslint.org/docs/rules/
    # https://github.com/typescript-eslint/typescript-eslint/tree/master/packages/eslint-plugin

    # !!!!!!!!!!!!!!!!!!!!!!!!!
    # BEFORE ADDING ANY RULES
    # PLEASE EXPLAIN THE REASON IN THE COMMENT.

    ##### RECOMMENDED RULE OVERRIDES #####

    camelcase: off # underscores may come in handy in some cases
    eqeqeq: warn # important check missing from recommended
    keyword-spacing: warn # we require this explicitly
    no-multi-spaces: off # useful for manually align some expression across lines
    prefer-rest-params: off # we need ES5 to be fast too
    prefer-spread: off # we need ES5 to be fast too
    space-before-function-paren: [warn, always] # we require this explicitly
    radix: off # we sometimes do not need to pass a second parameter
    # allow underscores, we still widely use pre-dangle naming in our naming convention
    # e.g. private properties, private functions, module scope shared variables etc.
    no-underscore-dangle: off
    quotes: [warn, single, { allowTemplateLiterals: true }] # force single, but allow template literal
    no-else-return: off # else-return is a common pattern which clearly expresses the control flow
    no-unused-expressions: off # taken over by '@typescript-eslint/no-unused-expressions'
    no-empty-function: off # taken over by '@typescript-eslint/no-empty-function'

    ##### AIRBNB-SPECIFIC RULE OVERRIDES #####

    class-methods-use-this: off # so empty functions could work
    guard-for-in: off # for-in is a efficient choice for plain objects
    import/export: off # so export declare namespace could work
    import/extensions: off # typescript doesn't support this
    import/no-unresolved: off # TODO: fix internal modules
    import/prefer-default-export: off # prefer named exports
    indent: [error, 4, {
      SwitchCase: 0,
      ignoredNodes: [ # https://stackoverflow.com/a/72897089
          "FunctionExpression > .params[decorators.length > 0]",
          "FunctionExpression > .params > :matches(Decorator, :not(:first-child))",
          "ClassBody.body > PropertyDefinition[decorators.length > 0] > .key",
      ]
    }]

    lines-between-class-members: off # be more lenient on member declarations
    max-classes-per-file: off # helper classes are common
    max-len: [warn, 150] # more lenient on max length per line
    no-console: error # prefer the uniform logging methods
    no-plusplus: off # allow increment/decrement operators
    no-continue: off # allow unlabeled continues
    no-mixed-operators: off # this is just cumbersome
    no-multi-assign: off # it is handy sometimes
    no-nested-ternary: off # it is handy sometimes
    no-param-reassign: off # the output object is passed as parameters all the time
    no-restricted-syntax: off # for-in is a efficient choice for plain objects
    no-return-assign: off # it is handy sometimes
    no-shadow: off # TODO: this throws false-positives?
    no-sequences: off # it is handy sometimes
    no-bitwise: off # we use this extensively
    no-use-before-define: off # just too much work
    no-useless-constructor: off # gives false-positives for empty constructor with parameter properties
    object-curly-newline: off # we want manual control over this
    one-var-declaration-per-line: off # auto-fix has order issues with `one-var`
    prefer-destructuring: off # auto-fix is not smart enough to merge different instances
    linebreak-style: off # we don't enforce this on everyone's dev environment for now
    spaced-comment: off # for license declarations
    default-case-last: off # Place default case clause to first make it more clear that this switch statement has handled all cases

    ##### TYPESCRIPT-SPECIFIC RULE OVERRIDES #####

    '@typescript-eslint/ban-ts-comment': [error, {
        'ts-expect-error': true,
        'ts-ignore': true,
        'ts-nocheck': true,
        'ts-check': false,
    }]
    '@typescript-eslint/no-unused-expressions': warn

    # TODO: this is just too much work
    '@typescript-eslint/explicit-module-boundary-types': off

    # NOTE: We don't want to rely on TS automatic type inference
    '@typescript-eslint/no-inferrable-types': off

    # TODO: sadly we still rely heavily on legacyCC
    '@typescript-eslint/no-unsafe-assignment': off
    '@typescript-eslint/no-unsafe-call': off
    '@typescript-eslint/no-unsafe-member-access': off

    '@typescript-eslint/no-unsafe-enum-comparison': off

    '@typescript-eslint/unbound-method': off # we exploit prototype methods sometimes to acheive better performace
    '@typescript-eslint/no-explicit-any': off # still relevant for some heavily templated usages

    '@typescript-eslint/no-empty-function': off # may become useful in some parent classes

    '@typescript-eslint/no-unused-vars': off # may become useful in some parent classes
    '@typescript-eslint/no-non-null-assertion': off # sometimes we just know better than the compiler
    '@typescript-eslint/no-namespace': [warn, { # we need to declare static properties
        allowDeclarations: true,
        allowDefinitionFiles: true
    }]
    '@typescript-eslint/restrict-template-expressions': [warn, { # concatenations of different types are common, e.g. hash calculations
        allowNumber: true,
        allowBoolean: true
    }]

    '@typescript-eslint/type-annotation-spacing': warn

    # We choose to use style `... as foo` since it's more common.
    # In the other hand, angle bracket style can be ambiguous with j/tsx syntax.
    # For example, https://babeljs.io/docs/en/babel-plugin-transform-typescript#istsx
    # forbids angle bracket style if `isTSX` is enabled.
    '@typescript-eslint/consistent-type-assertions': [error, {
        assertionStyle: 'as'
    }]

    # Prefer the interface style.
    '@typescript-eslint/consistent-type-definitions': [error, interface]
    '@typescript-eslint/explicit-function-return-type': [error, {
      allowIIFEs: true, # IIFEs are widely used, writing their signature twice is painful
    }]