.eslintrc.yml

root: true
parser: '@typescript-eslint/parser'
parserOptions:
  project: './functions/tsconfig.json'
plugins:
  - '@typescript-eslint'
rules:
  # ESLint
  no-var: error                                     # disallow use of var for variables
  camelcase: error                                  # require camelCase for naming
  key-spacing: error                                # require consistent spacing between key-value pairs
  comma-dangle: error                               # disallow lonely commas in last line
  block-spacing: error                              # require spacing in between curly braces for blocks
  spaced-comment: error                             # require space after comments
  space-in-parens: error                            # disallow spaces around parenthesis
  no-multi-spaces: error                            # disallow whitespace around expressions and declarations
  space-infix-ops: error                            # require spaces around operators
  func-call-spacing: error                          # disallow spaces between a function call
  no-trailing-spaces: error                         # disallow trailing whitespace
  no-floating-decimal: error                        # require floating decimals to be complete
  space-before-blocks: error                        # require space before curly brace for blocks
  no-whitespace-before-property: error              # disallow whitespace before accessing properties
  one-var:                                          # require one variable declaration per let/const
    - error
    - never
  no-mixed-spaces-and-tabs:                         # disallow tabs + spaces for indentation except for smart-tabs
    - error
    - smart-tabs
  no-multiple-empty-lines:                          # disallow more than one empty line
    - error
    - max: 1
  object-curly-spacing:                             # require space around curly braces for objects
    - error
    - always
  eol-last:                                         # disallow new line after end of file
    - error
    - never
  padded-blocks:                                    # disallow empty line in between blocks         
    - error
    - never
  curly:                                            # require curly braces for large blocks and consistent in branches
    - error
    - multi-or-nest
    - consistent
  quotes:                                           # require single-quotes instead of single
    - error
    - single
    - avoidEscape: true
  max-len:                                          # require lines to be less than X characters
    - error
    - tabWidth: 3
    - code: 120
      comments: 160
      ignoreStrings: true
      ignoreTemplateLiterals: true
      ignoreTrailingComments: true
  padding-line-between-statements:                  # require empty line for statements
    - error
    - blankLine: always                             # require empty line after const/let
      prev:
        - const
        - let
      next: "*"
    - blankLine: any                                # allow empty lines between const/let
      prev:
        - const
        - let
      next:
        - const
        - let
    - blankLine: always                             # require empty line before return statement
      prev: "*"
      next: return
  # Typescript
  '@typescript-eslint/no-floating-promises': error  # require to handle promise function directly
  brace-style: off
  '@typescript-eslint/brace-style':                 # require opening brace on same line, ending brace on a new line
    - error
    - stroustrup
    - allowSingleLine: true
  comma-spacing: off                                # require space after a comma that is not the end of the line
  '@typescript-eslint/comma-spacing':
    - error
    - before: false
      after: true
  indent: off                                       # require tab for indentations
  '@typescript-eslint/indent':
    - error
    - tab
    - SwitchCase: 1
  keyword-spacing: off                              # require spaces before/after a keyword 
  '@typescript-eslint/keyword-spacing':
    - error
    - before: true
      after: true
  semi: off                                         # require semicolons for JS statements
  '@typescript-eslint/semi':
    - error
    - always
    - omitLastInOneLineBlock: true