Update engine & content

Author: yoksel

.eslintrc.js

@@ -0,0 +1,25 @@
+module.exports = {
+  env: {
+    browser: true,
+    es6: true,
+    node: true
+  },
+  extends: ['standard'],
+  globals: {
+    Atomics: 'readonly',
+    SharedArrayBuffer: 'readonly'
+  },
+  parser: "babel-eslint",
+  parserOptions: {
+    ecmaVersion: 2018,
+    sourceType: 'module'
+  },
+  rules: {
+    semi: ['error', 'always'],
+    // fix: Cannot read property 'range' of null
+    //https://github.com/babel/babel-eslint/issues/681#issuecomment-420663038
+    'template-curly-spacing' : 'off',
+    indent : "off"
+  },
+  "ignorePatterns": ["**/*test.js"]
+}

.stylelintrc

@@ -0,0 +1,36 @@
+{
+  "extends": "stylelint-config-standard",
+  "rules": {
+    "indentation": 2,
+    "string-quotes": "double",
+    "no-duplicate-selectors": true,
+    "color-hex-case": "upper",
+    "color-hex-length": "short",
+    "selector-max-id": 0,
+    "selector-combinator-space-after": "always",
+    "selector-attribute-quotes": "always",
+    "selector-type-case": "upper",
+    "declaration-block-trailing-semicolon": "always",
+    "declaration-no-important": true,
+    "declaration-colon-space-before": "never",
+    "declaration-colon-space-after": "always-single-line",
+    "declaration-colon-newline-after": null,
+    "property-no-vendor-prefix": true,
+    "value-no-vendor-prefix": true,
+    "number-leading-zero": "never",
+    "function-url-quotes": "always",
+    "font-family-name-quotes": "always-where-required",
+    "comment-whitespace-inside": "always",
+    "comment-empty-line-before": null,
+    "custom-property-empty-line-before": null,
+    "at-rule-no-vendor-prefix": true,
+    "selector-pseudo-element-colon-notation": "double",
+    "selector-pseudo-class-parentheses-space-inside": "never",
+    "selector-no-vendor-prefix": true,
+    "media-feature-range-operator-space-before": "always",
+    "media-feature-range-operator-space-after": "always",
+    "media-feature-parentheses-space-inside": "always",
+    "media-feature-colon-space-before": "never",
+    "media-feature-colon-space-after": "always"
+  }
+}

constants.js

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+const TITLE = 'Flex Cheatsheet';
+const DESC = 'Demos for W3C CSS Flexbox Specification http://www.w3.org/TR/css-flexbox-1/';
+const URL = 'https://yoksel.github.io/flex-cheatsheet/';
+const IMAGE = '';
+const GITHUB = 'https://github.com/yoksel/flex-cheatsheet/';
+const COUNTER = ``;
+const HIGHLIGHT_GRID = 0;
+
+module.exports = {
+  TITLE,
+  DESC,
+  URL,
+  IMAGE,
+  GITHUB,
+  COUNTER,
+  HIGHLIGHT_GRID
+};