diff --git a/.eslintrc b/.eslintrc
index 132dcd6c1c..998aebcf59 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -168,6 +168,6 @@
         "no-plusplus": 0,
         "no-prototype-builtins": 2,
         "prefer-template": 2,
-        "template-curly-spacing": [2, "never"],
+        "template-curly-spacing": [2, "never"]
     }
 }
diff --git a/lib/rules/destructuring-assignment.js b/lib/rules/destructuring-assignment.js
index 9f7d28255f..db1f675d5f 100644
--- a/lib/rules/destructuring-assignment.js
+++ b/lib/rules/destructuring-assignment.js
@@ -127,7 +127,7 @@ module.exports = {
           handleSFCUsage(node);
         }
         if (classComponent) {
-          handleClassUsage(node, classComponent);
+          handleClassUsage(node);
         }
       },
 
diff --git a/lib/rules/jsx-closing-bracket-location.js b/lib/rules/jsx-closing-bracket-location.js
index 745d0df200..860f6f3871 100644
--- a/lib/rules/jsx-closing-bracket-location.js
+++ b/lib/rules/jsx-closing-bracket-location.js
@@ -153,10 +153,11 @@ module.exports = {
      * Get the characters used for indentation on the line to be matched
      * @param {Object} tokens Locations of the opening bracket, closing bracket and last prop
      * @param {String} expectedLocation Expected location for the closing bracket
-     * @param {Number} correctColumn Expected column for the closing bracket
+     * @param {Number} [correctColumn] Expected column for the closing bracket. Default to 0
      * @return {String} The characters used for indentation
      */
     function getIndentation(tokens, expectedLocation, correctColumn) {
+      correctColumn = correctColumn || 0;
       let indentation, spaces = [];
       switch (expectedLocation) {
         case 'props-aligned':
diff --git a/lib/rules/jsx-curly-brace-presence.js b/lib/rules/jsx-curly-brace-presence.js
index c9de7fa83f..0020934b1a 100755
--- a/lib/rules/jsx-curly-brace-presence.js
+++ b/lib/rules/jsx-curly-brace-presence.js
@@ -110,7 +110,7 @@ module.exports = {
 
     /**
      * Report and fix an unnecessary curly brace violation on a node
-     * @param {ASTNode} node - The AST node with an unnecessary JSX expression
+     * @param {ASTNode} JSXExpressionNode - The AST node with an unnecessary JSX expression
      */
     function reportUnnecessaryCurly(JSXExpressionNode) {
       context.report({
diff --git a/lib/rules/jsx-curly-spacing.js b/lib/rules/jsx-curly-spacing.js
index f1395e5d07..c684ed6465 100644
--- a/lib/rules/jsx-curly-spacing.js
+++ b/lib/rules/jsx-curly-spacing.js
@@ -156,8 +156,8 @@ module.exports = {
     /**
      * Trims text of whitespace between two ranges
      * @param {Fixer} fixer - the eslint fixer object
-     * @param {Location} fromLoc - the start location
-     * @param {Location} toLoc - the end location
+     * @param {number} fromLoc - the start location
+     * @param {number} toLoc - the end location
      * @param {string} mode - either 'start' or 'end'
      * @param {string=} spacing - a spacing value that will optionally add a space to the removed text
      * @returns {Object|*|{range, text}}
@@ -183,6 +183,7 @@ module.exports = {
     * Reports that there shouldn't be a newline after the first token
     * @param {ASTNode} node - The node to report in the event of an error.
     * @param {Token} token - The token to use for the report.
+    * @param {string} spacing
     * @returns {void}
     */
     function reportNoBeginningNewline(node, token, spacing) {
@@ -201,6 +202,7 @@ module.exports = {
     * Reports that there shouldn't be a newline before the last token
     * @param {ASTNode} node - The node to report in the event of an error.
     * @param {Token} token - The token to use for the report.
+    * @param {string} spacing
     * @returns {void}
     */
     function reportNoEndingNewline(node, token, spacing) {
diff --git a/lib/rules/jsx-indent-props.js b/lib/rules/jsx-indent-props.js
index 55844bb8c3..1509b64c89 100644
--- a/lib/rules/jsx-indent-props.js
+++ b/lib/rules/jsx-indent-props.js
@@ -59,6 +59,7 @@ module.exports = {
 
     const extraColumnStart = 0;
     let indentType = 'space';
+    /** @type {number|'first'} */
     let indentSize = 4;
 
     const sourceCode = context.getSourceCode();
@@ -126,7 +127,6 @@ module.exports = {
      * Check indent for nodes list
      * @param {ASTNode[]} nodes list of node objects
      * @param {Number} indent needed indent
-     * @param {Boolean} excludeCommas skip comma on start of line
      */
     function checkNodesIndent(nodes, indent) {
       nodes.forEach(node => {
diff --git a/lib/rules/jsx-indent.js b/lib/rules/jsx-indent.js
index d0f237ff45..4b133fc364 100644
--- a/lib/rules/jsx-indent.js
+++ b/lib/rules/jsx-indent.js
@@ -110,7 +110,7 @@ module.exports = {
      * @param {ASTNode} node Node violating the indent rule
      * @param {Number} needed Expected indentation character count
      * @param {Number} gotten Indentation character count in the actual node/code
-     * @param {Object} loc Error line and column location
+     * @param {Object} [loc] Error line and column location
      */
     function report(node, needed, gotten, loc) {
       const msgContext = {
@@ -141,8 +141,8 @@ module.exports = {
     /**
      * Get node indent
      * @param {ASTNode} node Node to examine
-     * @param {Boolean} byLastLine get indent of node's last line
-     * @param {Boolean} excludeCommas skip comma on start of line
+     * @param {Boolean} [byLastLine] get indent of node's last line
+     * @param {Boolean} [excludeCommas] skip comma on start of line
      * @return {Number} Indent
      */
     function getNodeIndent(node, byLastLine, excludeCommas) {
@@ -204,7 +204,7 @@ module.exports = {
      * Check indent for nodes list
      * @param {ASTNode} node The node to check
      * @param {Number} indent needed indent
-     * @param {Boolean} excludeCommas skip comma on start of line
+     * @param {Boolean} [excludeCommas] skip comma on start of line
      */
     function checkNodesIndent(node, indent, excludeCommas) {
       const nodeIndent = getNodeIndent(node, false, excludeCommas);
diff --git a/lib/rules/jsx-sort-props.js b/lib/rules/jsx-sort-props.js
index a0b83a4d06..75a5d45e78 100644
--- a/lib/rules/jsx-sort-props.js
+++ b/lib/rules/jsx-sort-props.js
@@ -75,7 +75,7 @@ function contextCompare(a, b, options) {
  * Create an array of arrays where each subarray is composed of attributes
  * that are considered sortable.
  * @param {Array<JSXSpreadAttribute|JSXAttribute>} attributes
- * @return {Array<Array<JSXAttribute>}
+ * @return {Array<Array<JSXAttribute>>}
  */
 function getGroupsOfSortableAttributes(attributes) {
   const sortableAttributeGroups = [];
@@ -156,7 +156,7 @@ const generateFixerFunction = (node, context, reservedList) => {
  * Checks if the `reservedFirst` option is valid
  * @param {Object} context The context of the rule
  * @param {Boolean|Array<String>} reservedFirst The `reservedFirst` option
- * @return {?Function} If an error is detected, a function to generate the error message, otherwise, `undefined`
+ * @return {Function|undefined} If an error is detected, a function to generate the error message, otherwise, `undefined`
  */
 // eslint-disable-next-line consistent-return
 function validateReservedFirstConfig(context, reservedFirst) {
diff --git a/lib/rules/no-danger-with-children.js b/lib/rules/no-danger-with-children.js
index d03546537c..af2af06672 100644
--- a/lib/rules/no-danger-with-children.js
+++ b/lib/rules/no-danger-with-children.js
@@ -28,6 +28,7 @@ module.exports = {
      * Takes a ObjectExpression and returns the value of the prop if it has it
      * @param {object} node - ObjectExpression node
      * @param {string} propName - name of the prop to look for
+     * @param {string[]} seenProps
      */
     function findObjectProp(node, propName, seenProps) {
       if (!node.properties) {
diff --git a/lib/rules/no-unknown-property.js b/lib/rules/no-unknown-property.js
index cc881a8a3b..25508df044 100644
--- a/lib/rules/no-unknown-property.js
+++ b/lib/rules/no-unknown-property.js
@@ -157,8 +157,8 @@ function isTagName(node) {
 
 /**
  * Extracts the tag name for the JSXAttribute
- * @param {Object} node - JSXAttribute being tested.
- * @returns {String} tag name
+ * @param {JSXAttribute} node - JSXAttribute being tested.
+ * @returns {String|null} tag name
  */
 function getTagName(node) {
   if (node && node.parent && node.parent.name && node.parent.name) {
@@ -193,7 +193,7 @@ function getStandardName(name) {
   if (SVGDOM_ATTRIBUTE_NAMES[name]) {
     return SVGDOM_ATTRIBUTE_NAMES[name];
   }
-  let i;
+  let i = -1;
   const found = DOM_PROPERTY_NAMES.some((element, index) => {
     i = index;
     return element.toLowerCase() === name;
diff --git a/lib/rules/no-unused-prop-types.js b/lib/rules/no-unused-prop-types.js
index 8aaf9f9d2f..79488f16c0 100644
--- a/lib/rules/no-unused-prop-types.js
+++ b/lib/rules/no-unused-prop-types.js
@@ -82,7 +82,7 @@ module.exports = {
     /**
      * Used to recursively loop through each declared prop type
      * @param {Object} component The component to process
-     * @param {Array} props List of props to validate
+     * @param {ASTNode[]|true} props List of props to validate
      */
     function reportUnusedPropType (component, props) {
       // Skip props that check instances
diff --git a/lib/rules/prefer-stateless-function.js b/lib/rules/prefer-stateless-function.js
index 1dd6e63204..0b848db87a 100644
--- a/lib/rules/prefer-stateless-function.js
+++ b/lib/rules/prefer-stateless-function.js
@@ -137,7 +137,7 @@ module.exports = {
      * Checks whether the parameters of a constructor and the arguments of `super()`
      * have the same values or not.
      * @see ESLint no-useless-constructor rule
-     * @param {ASTNode} ctorParams - The parameters of a constructor to check.
+     * @param {ASTNode[]} ctorParams - The parameters of a constructor to check.
      * @param {ASTNode} superArgs - The arguments of `super()` to check.
      * @returns {boolean} `true` if those have the same values.
      */
diff --git a/lib/rules/static-property-placement.js b/lib/rules/static-property-placement.js
index 19b3313f9b..995e1f6957 100644
--- a/lib/rules/static-property-placement.js
+++ b/lib/rules/static-property-placement.js
@@ -102,17 +102,17 @@ module.exports = {
 
     /**
      * Check if we should report this property node
-     * @param node
-     * @param expectedRule
+     * @param {ASTNode} node
+     * @param {string} expectedRule
      */
     function reportNodeIncorrectlyPositioned(node, expectedRule) {
       // Detect if this node is an expected property declaration adn return the property name
       const name = classProperties.find(propertyName => {
         if (propertiesToCheck[propertyName](node)) {
-          return propertyName;
+          return !!propertyName;
         }
 
-        return null;
+        return false;
       });
 
       // If name is set but the configured rule does not match expected then report error
diff --git a/lib/rules/style-prop-object.js b/lib/rules/style-prop-object.js
index 4a29d33d25..4b9f750be5 100644
--- a/lib/rules/style-prop-object.js
+++ b/lib/rules/style-prop-object.js
@@ -24,7 +24,7 @@ module.exports = {
 
   create: function(context) {
     /**
-     * @param {object} node An Identifier node
+     * @param {ASTNode} expression An Identifier node
      */
     function isNonNullaryLiteral(expression) {
       return expression.type === 'Literal' && expression.value !== null;
diff --git a/lib/types.d.ts b/lib/types.d.ts
new file mode 100644
index 0000000000..d1ae21f948
--- /dev/null
+++ b/lib/types.d.ts
@@ -0,0 +1,29 @@
+import eslint from 'eslint';
+import estree from 'estree';
+
+declare global {
+  interface ASTNode extends estree.BaseNode {
+    [_: string]: any; // TODO: fixme
+  }
+  type Scope = eslint.Scope.Scope;
+  type Token = eslint.AST.Token;
+  type Fixer = eslint.Rule.RuleFixer;
+  type JSXAttribute = ASTNode;
+  type JSXSpreadAttribute = ASTNode;
+
+  interface Context extends eslint.SourceCode {
+    getFirstTokens(node: estree.Node | ASTNode, options?: eslint.SourceCode.CursorWithCountOptions): eslint.AST.Token[];
+  }
+
+  type TypeDeclarationBuilder = (annotation: ASTNode, parentName: string, seen: Set<typeof annotation>) => object;
+
+  type TypeDeclarationBuilders = {
+    [k in string]: TypeDeclarationBuilder;
+  };
+
+  type UnionTypeDefinitionChildren = unknown[];
+  type UnionTypeDefinition = {
+    type: 'union' | 'shape';
+    children: UnionTypeDefinitionChildren | true;
+  };
+}
diff --git a/lib/util/Components.js b/lib/util/Components.js
index b9de462d2e..a2dd6f72e7 100644
--- a/lib/util/Components.js
+++ b/lib/util/Components.js
@@ -258,7 +258,7 @@ function componentRule(rule, context) {
     /**
      * Check if variable is destructured from pragma import
      *
-     * @param {variable} String The variable name to check
+     * @param {string} variable The variable name to check
      * @returns {Boolean} True if createElement is destructured from the pragma
      */
     isDestructuredFromPragmaImport: function(variable) {
@@ -351,7 +351,7 @@ function componentRule(rule, context) {
      * Check if the node is returning JSX
      *
      * @param {ASTNode} ASTnode The AST node being checked
-     * @param {Boolean} strict If true, in a ternary condition the node must return JSX in both cases
+     * @param {Boolean} [strict] If true, in a ternary condition the node must return JSX in both cases
      * @returns {Boolean} True if the node is returning JSX, false if not
      */
     isReturningJSX: function(ASTnode, strict) {
@@ -413,7 +413,7 @@ function componentRule(rule, context) {
      * Check if the node is returning JSX or null
      *
      * @param {ASTNode} ASTnode The AST node being checked
-     * @param {Boolean} strict If true, in a ternary condition the node must return JSX in both cases
+     * @param {Boolean} [strict] If true, in a ternary condition the node must return JSX in both cases
      * @returns {Boolean} True if the node is returning JSX or null, false if not
      */
     isReturningJSXOrNull(ASTNode, strict) {
diff --git a/lib/util/annotations.js b/lib/util/annotations.js
index 47f53fe56c..9586cec8c9 100644
--- a/lib/util/annotations.js
+++ b/lib/util/annotations.js
@@ -8,6 +8,7 @@
 /**
  * Checks if we are declaring a `props` argument with a flow type annotation.
  * @param {ASTNode} node The AST node being checked.
+ * @param {Object} context
  * @returns {Boolean} True if the node is a type annotated props declaration, false if not.
  */
 function isAnnotatedFunctionPropsDeclaration(node, context) {
diff --git a/lib/util/ast.js b/lib/util/ast.js
index 530c889e7f..746bdb9ade 100644
--- a/lib/util/ast.js
+++ b/lib/util/ast.js
@@ -6,7 +6,7 @@
 /**
  * Find a return statment in the current node
  *
- * @param {ASTNode} ASTnode The AST node being checked
+ * @param {ASTNode} node The AST node being checked
  */
 function findReturnStatement(node) {
   if (
@@ -114,7 +114,7 @@ function isNodeFirstInLine(context, node) {
 
 /**
  * Checks if the node is a function or arrow function expression.
- * @param {Object} context The node to check
+ * @param {ASTNode} node The node to check
  * @return {Boolean} true if it's a function-like expression
  */
 function isFunctionLikeExpression(node) {
@@ -123,7 +123,7 @@ function isFunctionLikeExpression(node) {
 
 /**
  * Checks if the node is a function.
- * @param {Object} context The node to check
+ * @param {ASTNode} node The node to check
  * @return {Boolean} true if it's a function
  */
 function isFunction(node) {
@@ -132,7 +132,7 @@ function isFunction(node) {
 
 /**
  * Checks if the node is an arrow function.
- * @param {Object} context The node to check
+ * @param {ASTNode} node The node to check
  * @return {Boolean} true if it's an arrow function
  */
 function isArrowFunction(node) {
@@ -141,7 +141,7 @@ function isArrowFunction(node) {
 
 /**
  * Checks if the node is a class.
- * @param {Object} context The node to check
+ * @param {ASTNode} node The node to check
  * @return {Boolean} true if it's a class
  */
 function isClass(node) {
diff --git a/lib/util/defaultProps.js b/lib/util/defaultProps.js
index 4b39c61c43..b7287e4b90 100644
--- a/lib/util/defaultProps.js
+++ b/lib/util/defaultProps.js
@@ -70,7 +70,7 @@ module.exports = function defaultPropsInstructions(context, components, utils) {
   /**
    * Adds defaultProps to the component passed in.
    * @param   {ASTNode}         component    The component to add the defaultProps to.
-   * @param   {String[]|String} defaultProps defaultProps to add to the component or the string "unresolved"
+   * @param   {Object[]|'unresolved'} defaultProps defaultProps to add to the component or the string "unresolved"
    *                                         if this component has defaultProps that can't be resolved.
    * @returns {void}
    */
diff --git a/lib/util/linkComponents.js b/lib/util/linkComponents.js
index 4abf502396..cb9847d1f0 100644
--- a/lib/util/linkComponents.js
+++ b/lib/util/linkComponents.js
@@ -3,12 +3,17 @@
  */
 'use strict';
 
+/** TODO: type {(string | { name: string, linkAttribute: string })[]} */
+/** @type {any} */
 const DEFAULT_LINK_COMPONENTS = ['a'];
 const DEFAULT_LINK_ATTRIBUTE = 'href';
 
 function getLinkComponents(context) {
   const settings = context.settings || {};
-  return new Map(DEFAULT_LINK_COMPONENTS.concat(settings.linkComponents || []).map(value => {
+  const linkComponents = /** @type {typeof DEFAULT_LINK_COMPONENTS} */ (
+    DEFAULT_LINK_COMPONENTS.concat(settings.linkComponents || [])
+  );
+  return new Map(linkComponents.map(value => {
     if (typeof value === 'string') {
       return [value, DEFAULT_LINK_ATTRIBUTE];
     }
diff --git a/lib/util/propTypes.js b/lib/util/propTypes.js
index 8d47b2563b..8485591822 100644
--- a/lib/util/propTypes.js
+++ b/lib/util/propTypes.js
@@ -26,7 +26,7 @@ function isSuperTypeParameterPropsDeclaration(node) {
 
 /**
  * Removes quotes from around an identifier.
- * @param {string} the identifier to strip
+ * @param {string} string the identifier to strip
  */
 function stripQuotes(string) {
   return string.replace(/^\'|\'$/g, '');
@@ -34,6 +34,7 @@ function stripQuotes(string) {
 
 /**
  * Retrieve the name of a key node
+ * @param {Context} context The AST node with the key.
  * @param {ASTNode} node The AST node with the key.
  * @return {string} the name of the key
  */
@@ -51,6 +52,7 @@ function getKeyValue(context, node) {
 
 /**
  * Iterates through a properties node, like a customized forEach.
+ * @param {Object} context Array of properties to iterate.
  * @param {Object[]} properties Array of properties to iterate.
  * @param {Function} fn Function to call on each property, receives property key
     and property value. (key, value) => void
@@ -134,6 +136,7 @@ module.exports = function propTypesInstructions(context, components, utils) {
   }
 
   /* eslint-disable no-use-before-define */
+  /** @type {TypeDeclarationBuilders} */
   const typeDeclarationBuilders = {
     GenericTypeAnnotation: function(annotation, parentName, seen) {
       if (getInTypeScope(annotation.id.name)) {
@@ -170,6 +173,7 @@ module.exports = function propTypesInstructions(context, components, utils) {
     },
 
     UnionTypeAnnotation: function(annotation, parentName, seen) {
+      /** @type {UnionTypeDefinition} */
       const unionTypeDefinition = {
         type: 'union',
         children: []
@@ -185,9 +189,9 @@ module.exports = function propTypesInstructions(context, components, utils) {
           }
         }
 
-        unionTypeDefinition.children.push(type);
+        /** @type {UnionTypeDefinitionChildren} */(unionTypeDefinition.children).push(type);
       }
-      if (unionTypeDefinition.children.length === 0) {
+      if (/** @type {UnionTypeDefinitionChildren} */(unionTypeDefinition.children).length === 0) {
         // no complex type found, simply accept everything
         return {};
       }
@@ -236,6 +240,8 @@ module.exports = function propTypesInstructions(context, components, utils) {
    * Creates the representation of the React props type annotation for the component.
    * The representation is used to verify nested used properties.
    * @param {ASTNode} annotation Type annotation for the props class property.
+   * @param {String} parentName
+   * @param {Set<ASTNode>} [seen]
    * @return {Object} The representation of the declaration, empty object means
    *    the property is declared without the need for further analysis.
    */
@@ -325,6 +331,7 @@ module.exports = function propTypesInstructions(context, components, utils) {
    * Creates the representation of the React propTypes for the component.
    * The representation is used to verify nested used properties.
    * @param {ASTNode} value Node of the PropTypes for the desired property
+   * @param {string} parentName
    * @return {Object} The representation of the declaration, empty object means
    *    the property is declared without the need for further analysis.
    */
@@ -402,6 +409,8 @@ module.exports = function propTypesInstructions(context, components, utils) {
             // Invalid proptype or cannot analyse statically
             return {};
           }
+
+          /** @type {UnionTypeDefinition} */
           const unionTypeDefinition = {
             type: 'union',
             children: []
@@ -417,9 +426,9 @@ module.exports = function propTypesInstructions(context, components, utils) {
               }
             }
 
-            unionTypeDefinition.children.push(type);
+            /** @type {UnionTypeDefinitionChildren} */(unionTypeDefinition.children).push(type);
           }
-          if (unionTypeDefinition.length === 0) {
+          if (/** @type {UnionTypeDefinitionChildren} */(unionTypeDefinition.children).length === 0) {
             // no complex type found, simply accept everything
             return {};
           }
@@ -443,7 +452,7 @@ module.exports = function propTypesInstructions(context, components, utils) {
   /**
    * Mark a prop type as declared
    * @param {ASTNode} node The AST node being checked.
-   * @param {propTypes} node The AST node containing the proptypes
+   * @param {ASTNode} propTypes The AST node containing the proptypes
    */
   function markPropTypesAsDeclared(node, propTypes) {
     let componentNode = node;
diff --git a/lib/util/props.js b/lib/util/props.js
index 66f6042fff..f8b7171b30 100644
--- a/lib/util/props.js
+++ b/lib/util/props.js
@@ -65,7 +65,7 @@ function isDefaultPropsDeclaration(node) {
 
 /**
  * Checks if we are declaring a display name
- * @param {node} node The AST node being checked.
+ * @param {ASTNode} node The AST node being checked.
  * @returns {Boolean} True if we are declaring a display name, false if not.
  */
 function isDisplayNameDeclaration(node) {
diff --git a/lib/util/usedPropTypes.js b/lib/util/usedPropTypes.js
index aea9f8093e..f57d2e636b 100755
--- a/lib/util/usedPropTypes.js
+++ b/lib/util/usedPropTypes.js
@@ -90,7 +90,7 @@ module.exports = function usedPropTypesInstructions(context, components, utils)
    * @return {Boolean} True if the node is a lifecycle method
    */
   function isNodeALifeCycleMethod(node) {
-    const nodeKeyName = (node.key || {}).name;
+    const nodeKeyName = (node.key || /** @type {ASTNode} */ ({})).name;
 
     if (node.kind === 'constructor') {
       return true;
@@ -177,7 +177,7 @@ module.exports = function usedPropTypesInstructions(context, components, utils)
 
   /**
    * Removes quotes from around an identifier.
-   * @param {string} the identifier to strip
+   * @param {string} string the identifier to strip
    */
   function stripQuotes(string) {
     return string.replace(/^\'|\'$/g, '');
@@ -203,7 +203,7 @@ module.exports = function usedPropTypesInstructions(context, components, utils)
   /**
    * Retrieve the name of a property node
    * @param {ASTNode} node The AST node with the property.
-   * @return {string} the name of the property or undefined if not found
+   * @return {string|undefined} the name of the property or undefined if not found
    */
   function getPropertyName(node) {
     const isDirectProp = DIRECT_PROPS_REGEX.test(sourceCode.getText(node));
@@ -283,6 +283,7 @@ module.exports = function usedPropTypesInstructions(context, components, utils)
   /**
    * Mark a prop type as used
    * @param {ASTNode} node The AST node being marked.
+   * @param {string[]} [parentNames]
    */
   function markPropTypesAsUsed(node, parentNames) {
     parentNames = parentNames || [];
diff --git a/lib/util/variable.js b/lib/util/variable.js
index 30137c8364..73b761c164 100644
--- a/lib/util/variable.js
+++ b/lib/util/variable.js
@@ -7,7 +7,7 @@
 /**
  * Search a particular variable in a list
  * @param {Array} variables The variables list.
- * @param {Array} name The name of the variable to search.
+ * @param {string} name The name of the variable to search.
  * @returns {Boolean} True if the variable was found, false if not.
  */
 function findVariable(variables, name) {
@@ -17,7 +17,7 @@ function findVariable(variables, name) {
 /**
  * Find and return a particular variable in a list
  * @param {Array} variables The variables list.
- * @param {Array} name The name of the variable to search.
+ * @param {string} name The name of the variable to search.
  * @returns {Object} Variable if the variable was found, null if not.
  */
 function getVariable(variables, name) {
diff --git a/package.json b/package.json
index b88898512c..0c499017e3 100644
--- a/package.json
+++ b/package.json
@@ -7,8 +7,10 @@
   "scripts": {
     "coveralls": "cat ./reports/coverage/lcov.info | coveralls",
     "lint": "eslint ./",
+    "postlint": "npm run type-check",
     "pretest": "npm run lint",
     "test": "npm run unit-test",
+    "type-check": "tsc",
     "unit-test": "istanbul cover --dir reports/coverage node_modules/mocha/bin/_mocha tests/lib/**/*.js tests/util/**/*.js tests/index.js"
   },
   "files": [
@@ -33,6 +35,9 @@
     "resolve": "^1.10.1"
   },
   "devDependencies": {
+    "@types/eslint": "^4.16.6",
+    "@types/estree": "0.0.39",
+    "@types/node": "^12.0.0",
     "babel-eslint": "^8.2.6",
     "coveralls": "^3.0.2",
     "eslint": "^3.0.0 || ^4.0.0 || ^5.0.0",
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000000..a8ecf2b575
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,22 @@
+{
+  "compilerOptions": {
+    "target": "ES2015",       /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */
+    "module": "commonjs",     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
+    // "lib": ["es2015"],        /* Specify library files to be included in the compilation. */
+    "allowJs": true,          /* Allow javascript files to be compiled. */
+    "checkJs": true,          /* Report errors in .js files. */
+    "noEmit": true,           /* Do not emit outputs. */
+    "esModuleInterop": true,   /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
+
+    /* Strict Type-Checking Options */
+    // "strict": true,                        /* Enable all strict type-checking options. */
+    "noImplicitAny": false,                /* Raise error on expressions and declarations with an implied 'any' type. */
+    // "strictNullChecks": true,              /* Enable strict null checks. */
+    // "strictPropertyInitialization": true,  /* Enable strict checking of property initialization in classes. */
+    "strictFunctionTypes": true,           /* Enable strict checking of function types. */
+    "strictBindCallApply": true,           /* Enable strict 'bind', 'call', and 'apply' methods on functions. */
+    "noImplicitThis": true,                /* Raise error on 'this' expressions with an implied 'any' type. */
+    "alwaysStrict": false,                 /* Parse in strict mode and emit "use strict" for each source file. */
+  },
+  "include": ["lib"],
+}