Sane default eslintrc close to Salesforce DX.

.eslintrc.json

{
  "env": {
    "browser": true
  },
  "parserOptions": {
    "ecmaVersion": 5
  },
  "globals": {
    "$A": true,
    "AuraContext": true,
    "AuraSerializationService": true,
    "AuraExpressionService": true,
    "AuraEventService": true,
    "AuraLocalizationService": true,
    "AuraStorageService": true,
    "AuraStyleService": true,
    "MetricsService": true,
    "AuraDevToolService": true,
    "Component": true,
    "CKEDITOR": true,
    "FORCE": true,
    "moment": true,
    "exports": true,
    "iScroll": true,
    "unescape": true,
    "Promise": true
  },
  "rules": {
    "no-alert": 2,
    "no-array-constructor": 2,
    "no-bitwise": 1,
    "no-caller": 2,
    "no-catch-shadow": 2,
    "no-cond-assign": 2,
    "no-console": 2,
    "no-constant-condition": 2,
    "no-control-regex": 1,
    "no-debugger": 2,
    "no-delete-var": 1,
    "no-div-regex": 1,
    "no-dupe-keys": 2,
    "no-dupe-args": 2,
    "no-duplicate-case": 2,
    "no-else-return": 0,
    "no-empty-character-class": 2,
    "no-eq-null": 1,
    "no-eval": 2,
    "no-ex-assign": 2,
    "no-extend-native": 2,
    "no-extra-bind": 2,
    "no-extra-boolean-cast": 2,
    "no-fallthrough": 2,
    "no-floating-decimal": 1,
    "no-func-assign": 2,
    "no-implied-eval": 2,
    "no-inner-declarations": [2, "functions"],
    "no-invalid-regexp": 2,
    "no-irregular-whitespace": 2,
    "no-iterator": 2,
    "no-label-var": 2,
    "no-labels": 2,
    "no-loop-func": 2,
    "no-multi-str": 2,
    "no-native-reassign": 2,
    "no-negated-in-lhs": 2,
    "no-nested-ternary": 1,
    "no-new": 2,
    "no-new-func": 2,
    "no-new-object": 2,
    "no-new-wrappers": 2,
    "no-obj-calls": 2,
    "no-octal": 2,
    "no-octal-escape": 2,
    "no-param-reassign": 1,
    "no-plusplus": 1,
    "no-proto": 2,
    "no-redeclare": 2,
    "no-regex-spaces": 2,
    "no-return-assign": 2,
    "no-script-url": 2,
    "no-self-compare": 2,
    "no-sequences": 2,
    "no-shadow": 2,
    "no-shadow-restricted-names": 2,
    "no-sparse-arrays": 2,
    "no-ternary": 0,
    "no-throw-literal": 1,
    "no-undef": 1,
    "no-undef-init": 1,
    "no-undefined": 0,
    "no-underscore-dangle": 0,
    "no-unreachable": 2,
    "no-unused-expressions": 1,
    "no-unused-vars": [1, {
      "vars": "all",
      "args": "after-used"
    }],
    "no-use-before-define": [2, {
      "functions": false
    }],
    "no-void": 2,
    "no-var": 0,
    "no-with": 2,
    "consistent-return": 1,
    "default-case": 2,
    "dot-notation": [1, {
      "allowKeywords": true
    }],
    "eqeqeq": ["error", "smart"],
    "guard-for-in": 1,
    "handle-callback-err": 1,
    "new-parens": 2,
    "radix": 2,
    "strict": [1, "global"],
    "use-isnan": 2,
    "valid-typeof": 2,
    "wrap-iife": [1, "any"],
    "no-trailing-spaces": 1,
    "no-spaced-func": 1,
    "no-mixed-spaces-and-tabs": 0,
    "no-multi-spaces": 0,
    "no-multiple-empty-lines": 0,
    "no-lone-blocks": 1,
    "no-lonely-if": 1,
    "no-inline-comments": 0,
    "no-extra-parens": 0,
    "no-extra-semi": 1,
    "no-warning-comments": [0, {
      "terms": ["todo", "fixme", "xxx"],
      "location": "start"
    }],
    "block-scoped-var": 1,
    "brace-style": [1, "1tbs"],
    "camelcase": 1,
    "comma-dangle": [1, "never"],
    "comma-spacing": 1,
    "comma-style": 1,
    "complexity": [0, 11],
    "consistent-this": [0, "that"],
    "curly": [1, "all"],
    "eol-last": 0,
    "func-names": 0,
    "func-style": [0, "declaration"],
    "generator-star-spacing": 0,
    "indent": 0,
    "key-spacing": 0,
    "keyword-spacing": [0],
    "max-depth": [0, 4],
    "max-len": [0, 80, 4],
    "max-nested-callbacks": [0, 2],
    "max-params": [0, 3],
    "max-statements": [0, 10],
    "new-cap": 0,
    "newline-after-var": 0,
    "one-var": [0, "never"],
    "operator-assignment": [0, "always"],
    "padded-blocks": 0,
    "quote-props": 0,
    "quotes": 0,
    "semi": 1,
    "semi-spacing": [0, {
      "before": false,
      "after": true
    }],
    "sort-vars": 0,
    "space-after-function-name": [0, "never"],
    "space-before-blocks": [0, "always"],
    "space-before-function-paren": [0, "always"],
    "space-before-function-parentheses": [0, "always"],
    "space-in-brackets": [0, "never"],
    "space-in-parens": [0, "never"],
    "space-infix-ops": 0,
    "space-unary-ops": [1, {
      "words": true,
      "nonwords": false
    }],
    "spaced-comment": [0, "always"],
    "vars-on-top": 0,
    "valid-jsdoc": 0,
    "wrap-regex": 0,
    "yoda": [1, "never"]
  }
}