diff --git a/types/bardjs/index.d.ts b/types/bardjs/index.d.ts
index f701d4c368..8b533a9483 100644
--- a/types/bardjs/index.d.ts
+++ b/types/bardjs/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://github.com/wardbell/bardjs
 // Definitions by: Andrew Archibald <https://github.com/TepigMC>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.4
+// TypeScript Version: 3.0
 
 /// <reference types="angular" />
 /// <reference types="chai" />
diff --git a/types/chai-almost/index.d.ts b/types/chai-almost/index.d.ts
index 2f7a3ffdc7..e5131e2220 100644
--- a/types/chai-almost/index.d.ts
+++ b/types/chai-almost/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/nmuldavin/chai-almost#readme
 // Definitions by: Lennard Schulz <https://github.com/kclnn>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
@@ -29,5 +30,5 @@ declare global {
     }
 }
 
-declare function chaiAlmost(tolerance?: number): ((chai: any, utils: any) => void);
+declare function chaiAlmost(tolerance?: number): Chai.ChaiPlugin;
 export = chaiAlmost;
diff --git a/types/chai-arrays/index.d.ts b/types/chai-arrays/index.d.ts
index 1e61eec3ae..bab67e13bd 100644
--- a/types/chai-arrays/index.d.ts
+++ b/types/chai-arrays/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/GaneshSPatil/chai-arrays
 // Definitions by: Clément Prévot <https://github.com/clementprevot>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
@@ -27,11 +28,7 @@ declare global {
             sorted(val: any[], msg?: string): void;
         }
     }
-
-    interface Array<T> {
-        should: Chai.Assertion;
-    }
 }
 
-declare function chaiArrays(chai: any, utils: any): void;
+declare const chaiArrays: Chai.ChaiPlugin;
 export = chaiArrays;
diff --git a/types/chai-as-promised/index.d.ts b/types/chai-as-promised/index.d.ts
index 8a9716806c..e3a19cd761 100644
--- a/types/chai-as-promised/index.d.ts
+++ b/types/chai-as-promised/index.d.ts
@@ -6,18 +6,17 @@
 //                 Mike Lazer-Walker <https://github.com/lazerwalker>,
 //                 Matt Bishop <https://github.com/mattbishop>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
 declare module 'chai-as-promised' {
-    function chaiAsPromised(chai: any, utils: any): void;
-
-    namespace chaiAsPromised {
-        function transferPromiseness(assertion: Chai.PromisedAssertion, promise: PromiseLike<any>): void;
-
-        function transformAsserterArgs(values: any[]): any;
+    interface ChaiAsPromised extends Chai.ChaiPlugin {
+        transferPromiseness(assertion: Chai.PromisedAssertion, promise: PromiseLike<any>): void;
+        transformAsserterArgs(values: any[]): any;
     }
 
+    const chaiAsPromised: ChaiAsPromised;
     export = chaiAsPromised;
 }
 
diff --git a/types/chai-datetime/index.d.ts b/types/chai-datetime/index.d.ts
index be623a05d4..d23c7e5d1a 100644
--- a/types/chai-datetime/index.d.ts
+++ b/types/chai-datetime/index.d.ts
@@ -3,10 +3,11 @@
 // Definitions by: Cliff Burger <https://github.com/cliffburger>,
 //                 Matt Bishop <https://github.com/mattbishop>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
-declare function chaiDateTime(chai: any, utils: any): void;
+declare const chaiDateTime: Chai.ChaiPlugin;
 export = chaiDateTime;
 
 declare global {
diff --git a/types/chai-dom/index.d.ts b/types/chai-dom/index.d.ts
index c6ecc75326..5f75de46f8 100644
--- a/types/chai-dom/index.d.ts
+++ b/types/chai-dom/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/nathanboktae/chai-dom
 // Definitions by: Matt Lewis <https://github.com/mattlewis92>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
@@ -56,11 +57,6 @@ declare namespace Chai {
 }
 
 declare module "chai-dom" {
-
-    function chaiDom(chai: any, utils: any): void;
-
-    namespace chaiDom {
-    }
-
+    const chaiDom: Chai.ChaiPlugin;
     export = chaiDom;
 }
diff --git a/types/chai-enzyme/index.d.ts b/types/chai-enzyme/index.d.ts
index b238b194c5..1056b9f27b 100644
--- a/types/chai-enzyme/index.d.ts
+++ b/types/chai-enzyme/index.d.ts
@@ -177,7 +177,7 @@ declare module "chai-enzyme" {
     import { ShallowWrapper, ReactWrapper } from "enzyme";
 
     type DebugWrapper = ShallowWrapper<any,any> | Cheerio | ReactWrapper<any, any>;
-    function chaiEnzyMe(wrapper?: (debugWrapper: DebugWrapper) => string): (chai: any) => void;
+    function chaiEnzyMe(wrapper?: (debugWrapper: DebugWrapper) => string): Chai.ChaiPlugin;
 
     module chaiEnzyMe {
     }
diff --git a/types/chai-fs/index.d.ts b/types/chai-fs/index.d.ts
index 3b82eee078..ac0d2654dd 100644
--- a/types/chai-fs/index.d.ts
+++ b/types/chai-fs/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://github.com/chaijs/chai-fs
 // Definitions by: Dimitar Danailov <https://github.com/dimitardanailov>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.2
+// TypeScript Version: 3.0
 
 /// <reference types="node" />
 /// <reference types="chai" />
@@ -214,7 +214,7 @@ declare global {
     }
 }
 
-declare function chaiFs(chai: any, utils: any): void;
+declare const chaiFs: Chai.ChaiPlugin;
 export = chaiFs;
 
 interface Object {
diff --git a/types/chai-fuzzy/index.d.ts b/types/chai-fuzzy/index.d.ts
index b4f8c1191c..a8deae0842 100644
--- a/types/chai-fuzzy/index.d.ts
+++ b/types/chai-fuzzy/index.d.ts
@@ -2,6 +2,7 @@
 // Project: http://chaijs.com/plugins/chai-fuzzy
 // Definitions by: Bart van der Schoor <https://github.com/Bartvds>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
@@ -71,6 +72,6 @@ declare global {
 	}
 }
 
-declare function chaiFuzzy(chai: any, utils: any): void;
+declare const chaiFuzzy: Chai.ChaiPlugin;
 export = chaiFuzzy;
 
diff --git a/types/chai-jest-snapshot/index.d.ts b/types/chai-jest-snapshot/index.d.ts
index 27ec049b14..4a8a9feaa1 100644
--- a/types/chai-jest-snapshot/index.d.ts
+++ b/types/chai-jest-snapshot/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://github.com/suchipi/chai-jest-snapshot#readme
 // Definitions by: Matt Perry <https://github.com/mattvperry>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.1
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 /// <reference types="mocha" />
@@ -17,10 +17,7 @@ declare global {
     }
 }
 
-interface ChaiJestSnapshot {
-    /** Chai bootstrapper */
-    (chai: any, utils: any): void;
-
+interface ChaiJestSnapshot extends Chai.ChaiPlugin {
     /** Set snapshot file name */
     setFilename(filename: string): void;
 
diff --git a/types/chai-jquery/index.d.ts b/types/chai-jquery/index.d.ts
index c2827d2e05..841492b20a 100644
--- a/types/chai-jquery/index.d.ts
+++ b/types/chai-jquery/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://github.com/chaijs/chai-jquery
 // Definitions by: Kazi Manzur Rashid <https://github.com/kazimanzurrashid>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.3
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 /// <reference types="jquery" />
diff --git a/types/chai-json-schema/index.d.ts b/types/chai-json-schema/index.d.ts
index 04e841bc91..1456fd8f73 100644
--- a/types/chai-json-schema/index.d.ts
+++ b/types/chai-json-schema/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/chaijs/chai-json-schema/, http://chaijs.com
 // Definitions by: Ulrich Heiniger <https://github.com/ulrichheiniger>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 // <reference types="node"/>
 // <reference types="chai" />
@@ -24,6 +25,6 @@ declare global {
 	}
 }
 
-declare function chaiJsonSchema(chai: any, utils: any): void;
+declare const chaiJsonSchema: Chai.ChaiPlugin;
 declare namespace chaiJsonSchema { }
 export = chaiJsonSchema;
diff --git a/types/chai-moment/chai-moment-tests.ts b/types/chai-moment/chai-moment-tests.ts
index 6354c4796b..18486a6032 100644
--- a/types/chai-moment/chai-moment-tests.ts
+++ b/types/chai-moment/chai-moment-tests.ts
@@ -3,10 +3,12 @@ import chaiMoment = require('chai-moment');
 
 use(chaiMoment);
 
+const g: ChaiMoment.Granularity = 'month';
+
 // bdd style
 expect('2019-03-14').to.be.afterMoment('2019-03-12', 'day');
 expect('2019-03-14').to.be.beforeMoment('2019-03-16');
-expect('2019-03-14').to.be.sameMoment('2019-03-14', 'day');
+expect('2019-03-14').to.be.sameMoment('2019-03-14', g);
 
 // tdd style
 assert.afterMoment('2019-03-14', '2019-03-12');
diff --git a/types/chai-moment/index.d.ts b/types/chai-moment/index.d.ts
index 0b19b7573f..fc67024319 100644
--- a/types/chai-moment/index.d.ts
+++ b/types/chai-moment/index.d.ts
@@ -2,24 +2,32 @@
 // Project: https://github.com/picardy/chai-moment
 // Definitions by: Chris Godsey <https://github.com/chrisgodsey>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
 declare global {
-	namespace Chai {
-		interface Assertion extends LanguageChains, NumericComparison, TypeComparison {
-            afterMoment(expected: string, granularity?: string): void;
-            beforeMoment(expected: string, granularity?: string): void;
-            sameMoment(expected: string, granularity?: string): void;
-		}
+    namespace ChaiMoment {
+        type Granularity = 'year' | 'month' | 'week' | 'day' | 'hour' | 'minute' | 'second';
+    }
 
-		interface Assert {
-            afterMoment(val: any, exp: any, granularity?: any, msg?: any): void;
-            beforeMoment(val: any, exp: any, granularity?: any, msg?: any): void;
-            sameMoment(val: any, exp: any, granularity?: any, msg?: any): void;
-		}
-	}
+    namespace Chai {
+        interface Assertion {
+            afterMoment(expected: any, granularity?: ChaiMoment.Granularity): void;
+            beforeMoment(expected: any, granularity?: ChaiMoment.Granularity): void;
+            sameMoment(expected: any, granularity?: ChaiMoment.Granularity): void;
+        }
+
+        interface AssertStatic {
+            afterMoment(val: any, exp: any, granularity: ChaiMoment.Granularity, msg?: string): void;
+            afterMoment(val: any, exp: any, msg?: string): void;
+            beforeMoment(val: any, exp: any, granularity?: ChaiMoment.Granularity, msg?: string): void;
+            beforeMoment(val: any, exp: any, msg?: string): void;
+            sameMoment(val: any, exp: any, granularity?: ChaiMoment.Granularity, msg?: string): void;
+            sameMoment(val: any, exp: any, msg?: string): void;
+        }
+    }
 }
 
-declare function chaiMoment(chai: any, utils: any): void;
+declare const chaiMoment: Chai.ChaiPlugin;
 export = chaiMoment;
diff --git a/types/chai-oequal/index.d.ts b/types/chai-oequal/index.d.ts
index 78160c255e..50253bb773 100644
--- a/types/chai-oequal/index.d.ts
+++ b/types/chai-oequal/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/wrwrwr/chai-oequal
 // Definitions by: Mizunashi Mana <https://github.com/mizunashi-mana>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
@@ -22,7 +23,7 @@ declare namespace Chai {
 }
 
 declare module 'chai-oequal' {
-    function chaiOequal(chai: any, utils: any): void;
+    const chaiOequal: Chai.ChaiPlugin;
     namespace chaiOequal {}
     export = chaiOequal;
 }
diff --git a/types/chai-roughly/index.d.ts b/types/chai-roughly/index.d.ts
index c1f162ddb7..f7b8e90f14 100644
--- a/types/chai-roughly/index.d.ts
+++ b/types/chai-roughly/index.d.ts
@@ -2,6 +2,8 @@
 // Project: https://github.com/Turbo87/chai-roughly#readme
 // Definitions by: Tomasz Nguyen <https://github.com/swist>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
+
 /// <reference types="chai" />
 
 declare global {
@@ -22,6 +24,6 @@ declare global {
     }
 }
 
-declare function chaiRoughly(chai: any, utils: any): void;
+declare const chaiRoughly: Chai.ChaiPlugin;
 declare namespace chaiRoughly { }
 export = chaiRoughly;
diff --git a/types/chai-spies/index.d.ts b/types/chai-spies/index.d.ts
index bb37fa8cd4..8d485e3854 100644
--- a/types/chai-spies/index.d.ts
+++ b/types/chai-spies/index.d.ts
@@ -4,6 +4,7 @@
 //                 Harm van der Werf <https://github.com/harm-less>
 //                 Jouni Suorsa <https://github.com/jounisuo>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
diff --git a/types/chai-string/index.d.ts b/types/chai-string/index.d.ts
index fcf0fb9c23..2c1768b916 100644
--- a/types/chai-string/index.d.ts
+++ b/types/chai-string/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/onechiporenko/chai-string
 // Definitions by: Nick Malaguti <https://github.com/nmalaguti>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 ///<reference types="chai" />
 
@@ -48,6 +49,6 @@ declare global {
     }
 }
 
-declare function chaiString(chai: any, utils: any): void;
+declare const chaiString: Chai.ChaiPlugin;
 declare namespace chaiString { }
 export = chaiString;
diff --git a/types/chai-subset/index.d.ts b/types/chai-subset/index.d.ts
index d02efb5844..3e1511caad 100644
--- a/types/chai-subset/index.d.ts
+++ b/types/chai-subset/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/debitoor/chai-subset
 // Definitions by: Sam Noedel <https://github.com/delta62>, Andrew Brown <https://github.com/AGBrown>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
@@ -16,5 +17,5 @@ declare global {
     }
 }
 
-declare function chaiSubset(chai: any, utils: any): void;
+declare const chaiSubset: Chai.ChaiPlugin;
 export = chaiSubset;
diff --git a/types/chai-things/index.d.ts b/types/chai-things/index.d.ts
index e0b3d0f0ec..60b6812dbf 100644
--- a/types/chai-things/index.d.ts
+++ b/types/chai-things/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/chaijs/chai-things
 // Definitions by: David Broder-Rodgers <https://github.com/DavidBR-SW/>
 // Definitions: https://github.com/borisyankov/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
@@ -59,7 +60,7 @@ interface Array<T> {
 }
 
 declare module "chai-things" {
-    function chaiThings(chai: any, utils: any): void;
+    const chaiThings: Chai.ChaiPlugin;
     namespace chaiThings { }
     export = chaiThings;
 }
diff --git a/types/chai-uuid/index.d.ts b/types/chai-uuid/index.d.ts
index 23a0b6db92..bdc7cb5061 100644
--- a/types/chai-uuid/index.d.ts
+++ b/types/chai-uuid/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://github.com/rfrench/chai-uuid
 // Definitions by: Harm van der Werf <https://github.com/harm-less>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.8
+// TypeScript Version: 3.0
 
 /// <reference types="node" />
 /// <reference types="chai" />
@@ -23,5 +23,5 @@ declare global {
 	}
 }
 
-declare function chaiUuid(chai: any, utils: any): void;
+declare const chaiUuid: Chai.ChaiPlugin;
 export = chaiUuid;
diff --git a/types/chai-webdriverio/index.d.ts b/types/chai-webdriverio/index.d.ts
index d0b958dad5..3ca6f01fde 100644
--- a/types/chai-webdriverio/index.d.ts
+++ b/types/chai-webdriverio/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/marcodejongh/chai-webdriverio
 // Definitions by: Nikolai Orekhov <https://github.com/sherlock1982>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="webdriverio" />
 /// <reference types="chai" />
@@ -19,6 +20,6 @@ declare namespace Chai {
 }
 
 declare module 'chai-webdriverio' {
-    function chaiWebdriverIO(client: WebdriverIO.Client<void>, options?: any): (chai: any, utils: any) => void;
+    function chaiWebdriverIO(client: WebdriverIO.Client<void>, options?: any): Chai.ChaiPlugin;
     export = chaiWebdriverIO;
 }
diff --git a/types/chai-xml/index.d.ts b/types/chai-xml/index.d.ts
index 7f6a78f653..f54b33a2df 100644
--- a/types/chai-xml/index.d.ts
+++ b/types/chai-xml/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/krampstudio/chai-xml
 // Definitions by: Jeff Goddard <https://github.com/jedigo>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
@@ -34,5 +35,5 @@ declare namespace ChaiXml {
   }
 }
 
-declare  function chaiXml(chai: any, utils: any): void;
+declare const chaiXml: Chai.ChaiPlugin;
 export = chaiXml;
diff --git a/types/chai/chai-tests.ts b/types/chai/chai-tests.ts
index 36002d9bfa..228eb7c662 100644
--- a/types/chai/chai-tests.ts
+++ b/types/chai/chai-tests.ts
@@ -999,17 +999,91 @@ function _throw() {
 }
 
 function use() {
-    chai.use((_chai) => {
-        _chai.can.use.any();
-    });
+                   // Modified from:
+                   //   https://www.npmjs.com/package/chai-subset
+                   // But with added type annotations and some modifications to make the
+                   // linter whine less, and also a method (chai.assert.containSubset) removed
+                   // because we can't take advantage of namespace-declaration-merging here.
+                   function chaiSubset(chai: Chai.ChaiStatic, utils: Chai.ChaiUtils) {
+                       const Assertion = chai.Assertion;
+                       const assertionPrototype = Assertion.prototype;
 
-    const expect = chai
-        .use((_chai, util) => {
-        })
-        .use((_chai, util) => {
-        })
-        .expect;
-}
+                       Assertion.addMethod('containSubset', function(expected: Object) {
+                           const actual = utils.flag(this, 'object');
+                           const showDiff = chai.config.showDiff;
+
+                           assertionPrototype.assert.call(
+                               this,
+                               compare(expected, actual),
+                               'expected #{act} to contain subset #{exp}',
+                               'expected #{act} to not contain subset #{exp}',
+                               expected,
+                               actual,
+                               showDiff
+                           );
+                       });
+
+                       Assertion.addMethod('containSubset', function(expected: Object) {
+                           const actual = utils.flag(this, 'object');
+                           const showDiff = chai.config.showDiff;
+
+                           assertionPrototype.assert.call(
+                               this,
+                               compare(expected, actual),
+                               'expected #{act} to contain subset #{exp}',
+                               'expected #{act} to not contain subset #{exp}',
+                               expected,
+                               actual,
+                               showDiff
+                           );
+                       });
+
+                       function compare(expected: Object, actual: Object): boolean {
+                           if (expected === actual) {
+                               return true;
+                           }
+                           if (typeof actual !== typeof expected) {
+                               return false;
+                           }
+                           if (typeof expected !== 'object' || expected === null) {
+                               return expected === actual;
+                           }
+                           if (!!expected && !actual) {
+                               return false;
+                           }
+
+                           if (Array.isArray(expected) && Array.isArray(actual)) {
+                               if (typeof actual.length !== 'number') {
+                                   return false;
+                               }
+                               const aa = Array.prototype.slice.call(actual);
+                               return expected.every((exp: Object) => aa.some((act: Object) => compare(exp, act)));
+                           }
+
+                           if (expected instanceof Date) {
+                               if (actual instanceof Date) {
+                                   return expected.getTime() === actual.getTime();
+                               } else {
+                                   return false;
+                               }
+                           }
+
+                           return Object.keys(expected).every((key: string): boolean => {
+                               const eo = (expected as { [key: string]: Object })[key];
+                               const ao = (actual as { [key: string]: Object })[key];
+                               if (typeof eo === 'object' && eo !== null && ao !== null) {
+                                   return compare(eo, ao);
+                               }
+                               if (typeof eo === 'function') {
+                                   return eo(ao);
+                               }
+                               return ao === eo;
+                           });
+                       }
+                   }
+
+                   chai.use(chaiSubset);
+               }
 
 class Klass {
     val: number;
diff --git a/types/chai/index.d.ts b/types/chai/index.d.ts
index 5f73803757..1ee59343f1 100644
--- a/types/chai/index.d.ts
+++ b/types/chai/index.d.ts
@@ -1,4 +1,4 @@
-// Type definitions for chai 4.1
+// Type definitions for chai 4.2
 // Project: http://chaijs.com/
 // Definitions by: Jed Mao <https://github.com/jedmao>,
 //                 Bart van der Schoor <https://github.com/Bartvds>,
@@ -10,31 +10,147 @@
 //                 Gintautas Miselis <https://github.com/Naktibalda>
 //                 Satana Charuwichitratana <https://github.com/micksatana>
 //                 Erik Schierboom <https://github.com/ErikSchierboom>
+//                 Rebecca Turner <https://github.com/9999years>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 declare namespace Chai {
+    type Message = string | (() => string);
+    type ObjectProperty = string | symbol | number;
+
+    interface PathInfo {
+        parent: object;
+        name: string;
+        value?: any;
+        exists: boolean;
+    }
+
+    interface ErrorConstructor {
+        new(...args: any[]): Error;
+    }
+
+    interface ChaiUtils {
+        addChainableMethod(
+            // object to define the method on, e.g. chai.Assertion.prototype
+            ctx: object,
+            // method name
+            name: string,
+            // method itself; any arguments
+            method: (...args: any[]) => void,
+            // called when property is accessed
+            chainingBehavior?: () => void
+        ): void;
+        overwriteChainableMethod(
+            ctx: object,
+            name: string,
+            method: (...args: any[]) => void,
+            chainingBehavior?: () => void
+        ): void;
+        addLengthGuard(
+            fn: Function,
+            assertionName: string,
+            isChainable: boolean
+        ): void;
+        addMethod(ctx: object, name: string, method: Function): void;
+        addProperty(ctx: object, name: string, getter: () => any): void;
+        overwriteMethod(ctx: object, name: string, method: Function): void;
+        overwriteProperty(ctx: object, name: string, getter: () => any): void;
+        compareByInspect(a: object, b: object): -1 | 1;
+        expectTypes(obj: object, types: string[]): void;
+        flag(obj: object, key: string, value?: any): any;
+        getActual(obj: object, args: AssertionArgs): any;
+        getProperties(obj: object): string[];
+        getEnumerableProperties(obj: object): string[];
+        getOwnEnumerablePropertySymbols(obj: object): symbol[];
+        getOwnEnumerableProperties(obj: object): Array<string | symbol>;
+        getMessage(errorLike: Error | string): string;
+        getMessage(obj: any, args: AssertionArgs): string;
+        inspect(obj: any, showHidden?: boolean, depth?: number, colors?: boolean): void;
+        isProxyEnabled(): boolean;
+        objDisplay(obj: object): void;
+        proxify(obj: object, nonChainableMethodName: string): object;
+        test(obj: object, args: AssertionArgs): boolean;
+        transferFlags(assertion: Assertion, obj: object, includeAll?: boolean): void;
+        compatibleInstance(thrown: Error, errorLike: Error | ErrorConstructor): boolean;
+        compatibleConstructor(thrown: Error, errorLike: Error | ErrorConstructor): boolean;
+        compatibleMessage(thrown: Error, errMatcher: string | RegExp): boolean;
+        getConstructorName(constructorFn: Function): string;
+        getFuncName(constructorFn: Function): string | null;
+
+        // Reexports from pathval:
+        hasProperty(obj: object | undefined | null, name: ObjectProperty): boolean;
+        getPathInfo(obj: object, path: string): PathInfo;
+        getPathValue(obj: object, path: string): object | undefined;
+    }
+
+    type ChaiPlugin = (chai: ChaiStatic, utils: ChaiUtils) => void;
+
     interface ChaiStatic {
         expect: ExpectStatic;
         should(): Should;
         /**
          * Provides a way to extend the internals of Chai
          */
-        use(fn: (chai: any, utils: any) => void): ChaiStatic;
+        use(fn: ChaiPlugin): ChaiStatic;
+        util: ChaiUtils;
         assert: AssertStatic;
         config: Config;
+        Assertion: AssertionStatic;
         AssertionError: typeof AssertionError;
         version: string;
     }
 
-    export interface ExpectStatic extends AssertionStatic {
+    export interface ExpectStatic {
+        (val: any, message?: string): Assertion;
         fail(actual?: any, expected?: any, message?: string, operator?: Operator): void;
     }
 
     export interface AssertStatic extends Assert {
     }
 
-    export interface AssertionStatic {
-        (target: any, message?: string): Assertion;
+    // chai.Assertion.prototype.assert arguments
+    type AssertionArgs = [
+        // 'expression to be tested'
+        // This parameter is unused and the docs list its type as
+        // 'Philosophical', which is mentioned nowhere else in the source. Do
+        // with that what you will!
+        any,
+        Message, // message if value fails
+        Message, // message if negated value fails
+        any, // expected value
+        any?, // actual value
+        boolean? // showDiff
+    ];
+
+    export interface AssertionPrototype {
+        assert(...args: AssertionArgs): void;
+        _obj: any;
+    }
+
+    export interface AssertionStatic extends AssertionPrototype {
+        prototype: AssertionPrototype;
+
+        new (target: any, message?: string, ssfi?: Function, lockSsfi?: boolean): Assertion;
+
+        // Deprecated properties:
+        includeStack: boolean;
+        showDiff: boolean;
+
+        // Partials of functions on ChaiUtils:
+        addProperty(name: string, getter: (this: AssertionStatic) => any): void;
+        addMethod(name: string, method: (this: AssertionStatic, ...args: any[]) => any): void;
+        addChainableMethod(
+            name: string,
+            method: (this: AssertionStatic, ...args: any[]) => void,
+            chainingBehavior?: () => void
+        ): void;
+        overwriteProperty(name: string, getter: (this: AssertionStatic) => any): void;
+        overwriteMethod(name: string, method: (this: AssertionStatic, ...args: any[]) => any): void;
+        overwriteChainableMethod(
+            name: string,
+            method: (this: AssertionStatic, ...args: any[]) => void,
+            chainingBehavior?: () => void
+        ): void;
     }
 
     export type Operator = string; // "==" | "===" | ">" | ">=" | "<" | "<=" | "!=" | "!==";
@@ -165,7 +281,7 @@ declare namespace Chai {
     }
 
     interface InstanceOf {
-        (constructor: Object, message?: string): Assertion;
+        (constructor: any, message?: string): Assertion;
     }
 
     interface CloseTo {
@@ -220,7 +336,7 @@ declare namespace Chai {
     }
 
     interface Include {
-        (value: Object | string | number, message?: string): Assertion;
+        (value: any, message?: string): Assertion;
         keys: Keys;
         deep: Deep;
         ordered: Ordered;
@@ -1686,6 +1802,16 @@ declare namespace Chai {
          * Default: 40
          */
         truncateThreshold: number;
+
+        /**
+         * Default: true
+         */
+        useProxy: boolean;
+
+        /**
+         * Default: ['then', 'catch', 'inspect', 'toJSON']
+         */
+        proxyExcludedKeys: string[];
     }
 
     export class AssertionError {
diff --git a/types/d3kit/v1/index.d.ts b/types/d3kit/v1/index.d.ts
index 5da692ef1b..325ba6fe1d 100644
--- a/types/d3kit/v1/index.d.ts
+++ b/types/d3kit/v1/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://www.npmjs.com/package/d3kit
 // Definitions by: Morgan Benton <https://github.com/morphatic/>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 import * as d3 from "d3";
 
diff --git a/types/deep-equal-in-any-order/index.d.ts b/types/deep-equal-in-any-order/index.d.ts
index d0e646d64e..9110ce9c56 100644
--- a/types/deep-equal-in-any-order/index.d.ts
+++ b/types/deep-equal-in-any-order/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/oprogramador/deep-equal-in-any-order#readme
 // Definitions by: Bastien Caudan <https://github.com/bcaudan>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 declare global {
     namespace Chai {
@@ -11,5 +12,5 @@ declare global {
     }
 }
 
-declare function deepEqualInAnyOrder(chai: any, utils: any): void;
+declare const deepEqualInAnyOrder: Chai.ChaiPlugin;
 export = deepEqualInAnyOrder;
diff --git a/types/dirty-chai/index.d.ts b/types/dirty-chai/index.d.ts
index 24556edd4c..f350ad5c99 100644
--- a/types/dirty-chai/index.d.ts
+++ b/types/dirty-chai/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/prodatakey/dirty-chai
 // Definitions by: Piotr Roszatycki <https://github.com/dex4er>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 /// <reference types="chai-as-promised" />
@@ -24,5 +25,5 @@ declare global {
     }
 }
 
-declare function dirtyChai(chai: any, utils: any): void;
+declare const dirtyChai: Chai.ChaiPlugin;
 export = dirtyChai;
diff --git a/types/ember-mocha/index.d.ts b/types/ember-mocha/index.d.ts
index 69d2202f04..8d53775d9c 100644
--- a/types/ember-mocha/index.d.ts
+++ b/types/ember-mocha/index.d.ts
@@ -4,7 +4,7 @@
 //                 Simon Ihmig <https://github.com/simonihmig>
 //                 Mike North <https://github.com/mike-north>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.8
+// TypeScript Version: 3.0
 
 import { TestContext, ModuleCallbacks } from "ember-test-helpers";
 import Ember from 'ember';
diff --git a/types/hexo-log/index.d.ts b/types/hexo-log/index.d.ts
index 40640a3a36..a877d212c3 100644
--- a/types/hexo-log/index.d.ts
+++ b/types/hexo-log/index.d.ts
@@ -2,7 +2,7 @@
 // Project: http://hexo.io/
 // Definitions by: segayuu <https://github.com/segayuu>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.4
+// TypeScript Version: 3.0
 
 import bunyan = require('hexo-bunyan');
 import streams = require('stream');
diff --git a/types/hexo-util/index.d.ts b/types/hexo-util/index.d.ts
index 5a6be7f5a2..ccb993b22b 100644
--- a/types/hexo-util/index.d.ts
+++ b/types/hexo-util/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://hexo.io/
 // Definitions by: sega yuu <https://github.com/segayuu>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.2
+// TypeScript Version: 3.0
 
 /// <reference types="node" />
 
diff --git a/types/hexo/index.d.ts b/types/hexo/index.d.ts
index 0f3a9dcc78..3d926cda84 100644
--- a/types/hexo/index.d.ts
+++ b/types/hexo/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://hexo.io/
 // Definitions by: KentarouTakeda <https://github.com/kentarouTakeda>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.8
+// TypeScript Version: 3.0
 
 import EventEmitter = require('events');
 import moment = require('moment');
diff --git a/types/jsx-chai/index.d.ts b/types/jsx-chai/index.d.ts
index 4d76ebf66f..346dd87efa 100644
--- a/types/jsx-chai/index.d.ts
+++ b/types/jsx-chai/index.d.ts
@@ -2,17 +2,15 @@
 // Project: https://github.com/bkonkle/jsx-chai
 // Definitions by: Philipp Holzer <https://github.com/nupplaphil>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 
-
 interface JsxChaiStatic {
     jsxChai: jsxChaiFunction;
 }
 
-interface jsxChaiFunction {
-    (chai: any, utils: any): void;
-}
+type jsxChaiFunction = Chai.ChaiPlugin;
 
 declare var jsxChai: JsxChaiStatic;
 
diff --git a/types/karma-chai-sinon/index.d.ts b/types/karma-chai-sinon/index.d.ts
index 9a14f659e2..0b14373a99 100644
--- a/types/karma-chai-sinon/index.d.ts
+++ b/types/karma-chai-sinon/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://github.com/tubalmartin/karma-chai-sinon
 // Definitions by: Václav Ostrožlík <https://github.com/vasek17>
 // Definitions: https://github.com/borisyankov/DefinitelyTyped
-// TypeScript Version: 2.8
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 import Sinon = require('sinon');
diff --git a/types/karma-chai/index.d.ts b/types/karma-chai/index.d.ts
index 15c7010071..8b8da8fe99 100644
--- a/types/karma-chai/index.d.ts
+++ b/types/karma-chai/index.d.ts
@@ -2,6 +2,7 @@
 // Project: http://xdissent.github.io/karma-chai
 // Definitions by: JayAndCatchFire <https://github.com/JayAndCatchFire>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 3.0
 
 import chai = require('chai');
 
diff --git a/types/redux-test-utils/index.d.ts b/types/redux-test-utils/index.d.ts
index 2c5a36e441..8128dbf78d 100644
--- a/types/redux-test-utils/index.d.ts
+++ b/types/redux-test-utils/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://github.com/Knegusen/redux-test-utils#readme
 // Definitions by: Huw Martin <https://github.com/huwmartin>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.3
+// TypeScript Version: 3.0
 
 import { AnyAction, Store, Dispatch } from 'redux';
 
diff --git a/types/sinon-chai/index.d.ts b/types/sinon-chai/index.d.ts
index ad7c8cb857..5047809295 100644
--- a/types/sinon-chai/index.d.ts
+++ b/types/sinon-chai/index.d.ts
@@ -4,7 +4,7 @@
 //                 Jed Mao <https://github.com/jedmao>
 //                 Eyal Lapid <https://github.com/elpdpt>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.8
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 /// <reference types="sinon" />
@@ -104,6 +104,6 @@ declare global {
     }
 }
 
-declare function sinonChai(chai: any, utils: any): void;
+declare const sinonChai: Chai.ChaiPlugin;
 declare namespace sinonChai { }
 export = sinonChai;
diff --git a/types/sinon-chai/v2/index.d.ts b/types/sinon-chai/v2/index.d.ts
index cff6d0b3a2..86645121df 100644
--- a/types/sinon-chai/v2/index.d.ts
+++ b/types/sinon-chai/v2/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://github.com/domenic/sinon-chai
 // Definitions by: Kazi Manzur Rashid <https://github.com/kazimanzurrashid>, Jed Mao <https://github.com/jedmao>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.8
+// TypeScript Version: 3.0
 
 /// <reference types="chai" />
 /// <reference types="sinon" />
@@ -84,6 +84,6 @@ declare global {
     }
 }
 
-declare function sinonChai(chai: any, utils: any): void;
+declare const sinonChai: Chai.ChaiPlugin;
 declare namespace sinonChai { }
 export = sinonChai;