diff --git a/types/ace/index.d.ts b/types/ace/index.d.ts
index 7faa5da4f8..cd20b57f05 100644
--- a/types/ace/index.d.ts
+++ b/types/ace/index.d.ts
@@ -1223,7 +1223,7 @@ declare namespace AceAjax {
         /**
          * Returns `true` if the current `textInput` is in focus.
         **/
-        isFocused(): void;
+        isFocused(): boolean;
 
         /**
          * Blurs the current `textInput`.
diff --git a/types/alt/index.d.ts b/types/alt/index.d.ts
index 9094642e70..c95e1653b0 100644
--- a/types/alt/index.d.ts
+++ b/types/alt/index.d.ts
@@ -54,7 +54,7 @@ declare namespace AltJS {
   export type Source = {[name:string]: () => SourceModel<any>};
 
   export interface SourceModel<S> {
-    local(state:any, ...args: any[]):any;
+    local?(state:any, ...args: any[]):any;
     remote(state:any, ...args: any[]):Promise<S>;
     shouldFetch?(fetchFn:(...args:Array<any>) => boolean):void;
     loading?:(args:any) => void;
diff --git a/types/compression-webpack-plugin/compression-webpack-plugin-tests.ts b/types/compression-webpack-plugin/compression-webpack-plugin-tests.ts
index 423ca4cea7..a679b7f599 100644
--- a/types/compression-webpack-plugin/compression-webpack-plugin-tests.ts
+++ b/types/compression-webpack-plugin/compression-webpack-plugin-tests.ts
@@ -1,15 +1,76 @@
 import { Configuration } from 'webpack';
 import CompressionPlugin = require('compression-webpack-plugin');
 
-const c: Configuration = {
+new CompressionPlugin();
+
+new CompressionPlugin({
+    include: ["a"] as ReadonlyArray<string>,
+    exclude: [/a/g] as ReadonlyArray<RegExp>,
+    test: "a",
+});
+
+const config: Configuration = {
     plugins: [
         new CompressionPlugin({
-            asset: "[path].gz[query]",
             algorithm: "gzip",
             cache: true,
+            filename: "[path].gz[query]",
+            minRatio: 0.8,
             test: /\.js$|\.html$/,
             threshold: 10240,
-            minRatio: 0.8
+            deleteOriginalAssets: true
+        })
+    ]
+};
+
+const configDefaultAlgo = new CompressionPlugin({
+    compressionOptions: { level: 7 }
+});
+
+// $ExpectError
+new CompressionPlugin({ asset: "[path].gz[query]" });
+
+const zlib: Configuration = {
+    plugins: [
+        new CompressionPlugin({
+            algorithm: "deflate",
+            compressionOptions: {
+                flush: 5,
+                windowBits: 20,
+                level: 7
+            }
+        })
+    ]
+};
+
+const badZlib: Configuration = {
+    plugins: [
+        // $ExpectError
+        new CompressionPlugin({
+            algorithm: "deflate",
+            compressionOptions: 5
+        })
+    ]
+};
+
+function customAlgorithm(input: string, options: number, callback: (err: Error, result: Buffer) => void) {
+}
+
+const custom: Configuration = {
+    plugins: [
+        new CompressionPlugin({
+            algorithm: customAlgorithm,
+            compressionOptions: 5
+        })
+    ]
+};
+
+const badCustom: Configuration = {
+    plugins: [
+        // $ExpectError
+        new CompressionPlugin({
+            algorithm: customAlgorithm,
+            compressionOptions: { flush: 5 }
         })
     ]
 };
diff --git a/types/compression-webpack-plugin/index.d.ts b/types/compression-webpack-plugin/index.d.ts
index a7b38383ef..5d72f1fca8 100644
--- a/types/compression-webpack-plugin/index.d.ts
+++ b/types/compression-webpack-plugin/index.d.ts
@@ -1,42 +1,47 @@
-// Type definitions for compression-webpack-plugin 0.4
+// Type definitions for compression-webpack-plugin 2.0
 // Project: https://github.com/webpack-contrib/compression-webpack-plugin
 // Definitions by: Anton Kandybo <https://github.com/dublicator>
+//                 Rhys van der Waerden <https://github.com/rhys-vdw>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.3
+// TypeScript Version: 2.4
 
 import { Plugin } from 'webpack';
+import { ZlibOptions as ZlibCompressionOptions } from 'zlib';
 
 export = CompressionPlugin;
 
-declare class CompressionPlugin extends Plugin {
-    constructor(options?: CompressionPlugin.Options);
+declare class CompressionPlugin<O = any> extends Plugin {
+    constructor(options?: CompressionPlugin.Options<O>);
 }
 
 declare namespace CompressionPlugin {
-    interface Options {
-        asset?: string;
-        algorithm?: string;
+    type AlgorithmCallback = (error: Error | null, result: Buffer) => void;
+    type Algorithm<O> = (source: string, options: O, callback: AlgorithmCallback) => void;
+
+    // NOTE: These are the async compression algorithms on the zlib object.
+    type ZlibAlgorithm = 'deflate' | 'deflateRaw' | 'gzip';
+    type Pattern = string | RegExp | ReadonlyArray<RegExp> | ReadonlyArray<string>;
+
+    interface BaseOptions {
         cache?: boolean | string;
-        test?: RegExp | RegExp[];
-        regExp?: RegExp | RegExp[];
-        threshold?: number;
+        deleteOriginalAssets?: boolean;
+        exclude?: Pattern;
+        filename?: string;
+        include?: Pattern;
         minRatio?: number;
-
-        // zopfli options
-        verbose?: boolean;
-        verbose_more?: boolean;
-        numiterations?: number;
-        blocksplitting?: boolean;
-        blocksplittinglast?: boolean;
-        blocksplittingmax?: number;
-
-        // zlib options
-        level?: number;
-        flush?: number;
-        chunkSize?: number;
-        windowBits?: number;
-        memLevel?: number;
-        strategy?: number;
-        dictionary?: any;
+        test?: Pattern;
+        threshold?: number;
     }
+
+    interface ZlibOptions extends BaseOptions {
+        algorithm?: ZlibAlgorithm;
+        compressionOptions?: ZlibCompressionOptions;
+    }
+
+    interface CustomOptions<O> extends BaseOptions {
+        algorithm: Algorithm<O>;
+        compressionOptions?: O;
+    }
+
+    type Options<O> = ZlibOptions | CustomOptions<O>;
 }
diff --git a/types/dd-trace/dd-trace-tests.ts b/types/dd-trace/dd-trace-tests.ts
index f98a0853cf..cee1b6e3ee 100644
--- a/types/dd-trace/dd-trace-tests.ts
+++ b/types/dd-trace/dd-trace-tests.ts
@@ -6,11 +6,11 @@ tracer.init({
     service: "MyLovelyService",
     hostname: "localhost",
     port: 8126,
+    env: "dev",
     logger: {
         debug: msg => {},
         error: err => {},
-    },
-    tags: { tracerEnv: 'dev'}
+    }
 });
 
 function useWebFrameworkPlugin(plugin: "express" | "hapi" | "koa" | "restify") {
diff --git a/types/dd-trace/index.d.ts b/types/dd-trace/index.d.ts
index 43bfd7183f..a55b7f8de7 100644
--- a/types/dd-trace/index.d.ts
+++ b/types/dd-trace/index.d.ts
@@ -83,6 +83,11 @@ interface TracerOptions {
      */
     port?: number | string;
 
+    /**
+     * Set an application’s environment e.g. prod, pre-prod, stage.
+     */
+    env?: string;
+
     /**
      * Percentage of spans to sample as a float between 0 and 1.
      * @default 1
diff --git a/types/http-proxy-middleware/index.d.ts b/types/http-proxy-middleware/index.d.ts
index b48214b8f6..09b80e21c4 100644
--- a/types/http-proxy-middleware/index.d.ts
+++ b/types/http-proxy-middleware/index.d.ts
@@ -18,7 +18,7 @@ declare function proxy(config: proxy.Config): proxy.Proxy;
 declare function proxy(contextOrUri: string | string[] | proxy.Filter, config: proxy.Config): proxy.Proxy;
 
 declare namespace proxy {
-  type Filter = (pathanme: string, req: http.IncomingMessage) => boolean;
+  type Filter = (pathname: string, req: http.IncomingMessage) => boolean;
   type Logger = (...args: any[]) => void;
   interface LogProvider {
     log: Logger;
diff --git a/types/mapbox-gl/index.d.ts b/types/mapbox-gl/index.d.ts
index 384cea55b6..149d433a89 100644
--- a/types/mapbox-gl/index.d.ts
+++ b/types/mapbox-gl/index.d.ts
@@ -232,7 +232,7 @@ declare namespace mapboxgl {
         /**
          * The max number of pixels a user can shift the mouse pointer during a click for it to be
          * considered a valid click (as opposed to a mouse drag).
-         * 
+         *
          * @default 3
          */
         clickTolerance?: number;
@@ -242,7 +242,7 @@ declare namespace mapboxgl {
          * and Vector Tile web workers (this information is normally inaccessible from the main
          * Javascript thread). Information will be returned in a `resourceTiming` property of
          * relevant `data` events.
-         * 
+         *
          * @default false
          */
         collectResourceTiming?: boolean;
@@ -250,7 +250,7 @@ declare namespace mapboxgl {
         /**
          * If `true`, symbols from multiple sources can collide with each other during collision
          * detection. If `false`, collision detection is run separately for the symbols in each source.
-         * 
+         *
          * @default true
          */
         crossSourceCollisions?: boolean;
@@ -278,7 +278,7 @@ declare namespace mapboxgl {
          * Controls the duration of the fade-in/fade-out animation for label collisions, in milliseconds.
          * This setting affects all symbol layers. This setting does not affect the duration of runtime
          * styling transitions or raster tile cross-fading.
-         * 
+         *
          * @default 300
          */
         fadeDuration?: number;
@@ -297,14 +297,14 @@ declare namespace mapboxgl {
          * 'CJK Unified Ideographs' and 'Hangul Syllables' ranges. In these ranges, font settings from
          * the map's style will be ignored, except for font-weight keywords (light/regular/medium/bold).
          * The purpose of this option is to avoid bandwidth-intensive glyph server requests.
-         * 
+         *
          * @default null
          */
         localIdeographFontFamily?: string;
 
         /**
          * A string representing the position of the Mapbox wordmark on the map.
-         * 
+         *
          * @default "bottom-left"
          */
         logoPosition?: 'top-left' | 'top-right' | 'bottom-left' | 'bottom-right';
@@ -324,14 +324,14 @@ declare namespace mapboxgl {
         /**
          * The initial pitch (tilt) of the map, measured in degrees away from the plane of the
          * screen (0-60).
-         * 
+         *
          * @default 0
          */
         pitch?: number;
 
         /**
          * If `false`, the map's pitch (tilt) control with "drag to rotate" interaction will be disabled.
-         * 
+         *
          * @default true
          */
         pitchWithRotate?: boolean;
@@ -339,14 +339,14 @@ declare namespace mapboxgl {
         /**
          * If `false`, the map won't attempt to re-request tiles once they expire per their HTTP
          * `cacheControl`/`expires` headers.
-         * 
+         *
          * @default true
          */
         refreshExpiredTiles?: boolean;
 
         /**
          * If `true`, multiple copies of the world will be rendered, when zoomed out.
-         * 
+         *
          * @default true
          */
         renderWorldCopies?: boolean;
@@ -363,7 +363,7 @@ declare namespace mapboxgl {
         /**
          * A callback run before the Map makes a request for an external URL. The callback can be
          * used to modify the url, set headers, or set the credentials property for cross-origin requests.
-         * 
+         *
          * @default null
          */
         transformRequest?: TransformRequestFunction;
@@ -377,13 +377,13 @@ declare namespace mapboxgl {
         /**
          * The maximum number of tiles stored in the tile cache for a given source. If omitted, the
          * cache will be dynamically sized based on the current viewport.
-         * 
+         *
          * @default null
          */
         maxTileCacheSize?: number;
     }
 
-    export type ResourceType = 
+    export type ResourceType =
         | 'Unknown'
         | 'Style'
         | 'Source'
@@ -692,7 +692,7 @@ declare namespace mapboxgl {
         clusterMaxZoom?: number;
 
         lineMetrics?: boolean;
-        
+
         generateId?: boolean;
     }
 
@@ -1477,13 +1477,13 @@ declare namespace mapboxgl {
     }
 
     export interface HeatmapPaint {
-        'heatmap-radius'?: number | Expression;
+        'heatmap-radius'?: number | StyleFunction | Expression;
         'heatmap-radius-transition'?: Transition;
         'heatmap-weight'?: number | StyleFunction | Expression;
-        'heatmap-intensity'?: number | Expression;
+        'heatmap-intensity'?: number | StyleFunction | Expression;
         'heatmap-intensity-transition'?: Transition;
-        'heatmap-color'?: string | Expression;
-        'heatmap-opacity'?: number | Expression;
+        'heatmap-color'?: string | StyleFunction | Expression;
+        'heatmap-opacity'?: number | StyleFunction | Expression;
         'heatmap-opacity-transition'?: Transition;
     }
 
diff --git a/types/mem-fs/index.d.ts b/types/mem-fs/index.d.ts
index 4b1d8c4d14..6ab2c43c88 100644
--- a/types/mem-fs/index.d.ts
+++ b/types/mem-fs/index.d.ts
@@ -10,13 +10,13 @@ import { Transform } from 'stream';
 import * as File from 'vinyl';
 
 export interface Store extends EventEmitter {
-    add: (file: File, content: string) => void;
-    each: (callback: (file: File, index: number) => void) => void;
     get: (filepath: string) => File;
+    add: (file: File) => this;
+    each: (callback: (file: File, index: number) => void) => this;
     stream: () => Transform;
 }
 
-export function create(...args: any[]): Store;
+export function create(): Store;
 
 export namespace memFs {
 }
diff --git a/types/mem-fs/mem-fs-tests.ts b/types/mem-fs/mem-fs-tests.ts
index 9605c65ef7..3b20f30891 100644
--- a/types/mem-fs/mem-fs-tests.ts
+++ b/types/mem-fs/mem-fs-tests.ts
@@ -3,6 +3,6 @@ import * as fs from 'mem-fs';
 const store: fs.Store = fs.create();
 const file = store.get('hello');
 
-store.add(file, 'hahahahah');
-
-store.each(file => console.dir(store.get(file.path)));
+const file2 = store.add(file)
+    .each(file => console.dir(store.get(file.path)))
+    .get('test');
diff --git a/types/prompts/index.d.ts b/types/prompts/index.d.ts
index 7aa3f2ea63..7dc3a928a7 100644
--- a/types/prompts/index.d.ts
+++ b/types/prompts/index.d.ts
@@ -1,7 +1,8 @@
-// Type definitions for prompts 1.1
+// Type definitions for prompts 1.2
 // Project: https://github.com/terkelg/prompts
 // Definitions by: Berkay GURSOY <https://github.com/Berkays>
 //                 Daniel Perez Alvarez <https://github.com/danielpa9708>
+//                 Kamontat Chantrachirathumrong <https://github.com/kamontat>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.8
 
@@ -47,18 +48,19 @@ declare namespace prompts {
     interface Choice {
         title: string;
         value: string;
+        disable?: boolean;
     }
 
     interface Options {
-        onSubmit: (prompt: PromptObject, answer: any, answers: any[]) => void;
-        onCancel: (prompt: PromptObject, answers: any) => void;
+        onSubmit?: (prompt: PromptObject, answer: any, answers: any[]) => void;
+        onCancel?: (prompt: PromptObject, answers: any) => void;
     }
 
     interface PromptObject<T extends string = string> {
-        type: ValueOrFunc<string>;
+        type: ValueOrFunc<PromptType> | Falsy;
         name: ValueOrFunc<T>;
         message?: ValueOrFunc<string>;
-        initial?: string;
+        initial?: string | number | boolean;
         style?: string;
         format?: PrevCaller<T, void>;
         validate?: PrevCaller<T, void>;
@@ -85,5 +87,9 @@ declare namespace prompts {
         prompt: PromptObject
     ) => R;
 
+    type Falsy = false | null | undefined;
+
+    type PromptType = "text" | "password" | "invisible" | "number" | "confirm" | "list" | "toggle" | "select" | "multiselect" | "autocomplete";
+
     type ValueOrFunc<T extends string> = T | PrevCaller<T>;
 }
diff --git a/types/ramda/index.d.ts b/types/ramda/index.d.ts
index 48888c6ee5..026da15ec9 100644
--- a/types/ramda/index.d.ts
+++ b/types/ramda/index.d.ts
@@ -1123,6 +1123,7 @@ declare namespace R {
          * of the condition predicate.
          */
         ifElse(fn: Pred, onTrue: Arity1Fn, onFalse: Arity1Fn): Arity1Fn;
+        ifElse(fn: Pred, onTrue: Arity2Fn, onFalse: Arity2Fn): Arity2Fn;
 
         /**
          * Increments its argument.
diff --git a/types/ramda/ramda-tests.ts b/types/ramda/ramda-tests.ts
index 2bd9a55d2f..2e292ffd59 100644
--- a/types/ramda/ramda-tests.ts
+++ b/types/ramda/ramda-tests.ts
@@ -2657,6 +2657,17 @@ class Rectangle {
     flattenArrays([[[10], 123], [8, [10]], "hello"]); // => [[10, 123], [8, 10], "hello"]
 };
 
+() => {
+    const incCount = R.ifElse(
+        R.has('count'),
+        R.over(R.lensProp('count'), R.inc),
+        R.assoc('count', 1)
+      );
+      incCount({});           // => { count: 1 }
+      incCount({ count: 1 }); // => { count: 2 }
+      R.ifElse(R.identical, R.add as (a: number, b: number) => number, R.always(""))(2, 2); // https://goo.gl/CVUSs9
+};
+
 () => {
     R.isEmpty([1, 2, 3]); // => false
     R.isEmpty([]); // => true