diff --git a/types/moo/index.d.ts b/types/moo/index.d.ts
index 8bdc583cc9..9cf67c3299 100644
--- a/types/moo/index.d.ts
+++ b/types/moo/index.d.ts
@@ -1,6 +1,7 @@
-// Type definitions for moo 0.3
+// Type definitions for moo 0.4
 // Project: https://github.com/tjvr/moo#readme
 // Definitions by: Nikita Litvin <https://github.com/deltaidea>
+//                 Jörg Vehlow <https://github.com/MofX>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
 export as namespace moo;
@@ -14,33 +15,43 @@ export function compile(rules: Rules): Lexer;
 
 export function states(states: {[x: string]: Rules}, start?: string): Lexer;
 
-export interface Rules {
-    [x: string]: RegExp | string | string[] | {
-        match: RegExp | string | string[],
-        /**
-         * Moo tracks detailed information about the input for you.
-         * It will track line numbers, as long as you apply the `lineBreaks: true`
-         * option to any tokens which might contain newlines. Moo will try to warn you if you forget to do this.
-         */
-        lineBreaks?: boolean,
-        /**
-         * Moves the lexer to a new state, and pushes the old state onto the stack.
-         */
-        push?: string,
-        /**
-         * Returns to a previous state, by removing one or more states from the stack.
-         */
-        pop?: number,
-        /**
-         * Moves to a new state, but does not affect the stack.
-         */
-        next?: string,
-        /**
-         * You can have a token type that both matches tokens and contains error values.
-         */
-        error?: true
+export interface Rule {
+    match?: RegExp | string | string[];
+    /**
+     * Moo tracks detailed information about the input for you.
+     * It will track line numbers, as long as you apply the `lineBreaks: true`
+     * option to any tokens which might contain newlines. Moo will try to warn you if you forget to do this.
+     */
+    lineBreaks?: boolean;
+    /**
+     * Moves the lexer to a new state, and pushes the old state onto the stack.
+     */
+    push?: string;
+    /**
+     * Returns to a previous state, by removing one or more states from the stack.
+     */
+    pop?: number;
+    /**
+     * Moves to a new state, but does not affect the stack.
+     */
+    next?: string;
+    /**
+     * You can have a token type that both matches tokens and contains error values.
+     */
+    error?: true;
+    /**
+     * Moo doesn't allow capturing groups, but you can supply a transform function, value(),
+     * which will be called on the value before storing it in the Token object.
+     */
+    value?: (x: string) => string;
+
+    keywords?: {
+        [x: string]: string | string[]
     };
 }
+export interface Rules {
+    [x: string]: RegExp | string | string[] | Rule;
+}
 
 export interface Lexer {
     /**
@@ -59,12 +70,14 @@ export interface Lexer {
     /**
      * Empty the internal buffer of the lexer, and set the line, column, and offset counts back to their initial value.
      */
-    reset(chunk: string, state?: LexerState): void;
+    reset(chunk?: string, state?: LexerState): void;
     /**
      * Returns current state, which you can later pass it as the second argument
      * to reset() to explicitly control the internal state of the lexer.
      */
     save(): LexerState;
+
+    [Symbol.iterator](): Iterator<Token>;
 }
 
 export interface Token {
@@ -77,7 +90,7 @@ export interface Token {
      */
     type?: string;
     /**
-     * The contents of the capturing group (or the whole match, if the token RegExp doesn't define a capture).
+     * The match contents.
      */
     value: string;
     /**
@@ -85,9 +98,9 @@ export interface Token {
      */
     offset: number;
     /**
-     * The total length of the match (value may be shorter if you have capturing groups).
+     * The complete match.
      */
-    size: number;
+    text: string;
     /**
      * The number of line breaks found in the match. (Always zero if this rule has lineBreaks: false.)
      */
diff --git a/types/moo/moo-tests.ts b/types/moo/moo-tests.ts
index 52defb99ce..6f0c18ae2d 100644
--- a/types/moo/moo-tests.ts
+++ b/types/moo/moo-tests.ts
@@ -2,28 +2,73 @@ import * as moo from 'moo';
 
 let lexer = moo.compile({
     lparen: '(',
-    word:  /[a-z]+/,
+    word: /[a-z]+/,
     rparen: ')',
     keyword: ['while', 'if', 'else', 'moo', 'cows']
 });
 
+lexer = moo.compile({
+    WS: /[ \t]+/,
+    comment: /\/\/.*?$/,
+    number: /0|[1-9][0-9]*/,
+    string: /"(?:\\["\\]|[^\n"\\])*"/,
+    lparen: '(',
+    rparen: ')',
+    keyword: ['while', 'if', 'else', 'moo', 'cows'],
+    NL: { match: /\n/, lineBreaks: true },
+});
+
+lexer = moo.compile({
+    IDEN: {
+        match: /[a-zA-Z]+/, keywords: {
+            KW: ['while', 'if', 'else', 'moo', 'reloacows']
+        }
+    },
+    SPACE: { match: /\s+/, lineBreaks: true }
+});
+
+lexer = moo.compile({
+    name: {
+        match: /[a-zA-Z]+/, keywords: {
+            'kw-class': 'class',
+            'kw-def': 'def',
+            'kw-if': 'if',
+        }
+    }
+});
+
 lexer = moo.states({
     main: {
-        strstart: {match: '`', push: 'lit'},
-        ident:    /\w+/,
-        lbrace:   {match: '{', push: 'main'},
-        rbrace:   {match: '}', pop: 1},
-        colon:    ':',
-        space:    {match: /\s+/, lineBreaks: true},
+        strstart: { match: '`', push: 'lit' },
+        ident: /\w+/,
+        lbrace: { match: '{', push: 'main' },
+        rbrace: { match: '}', pop: 1 },
+        colon: ':',
+        space: { match: /\s+/, lineBreaks: true },
     },
     lit: {
-        interp:   {match: '${', push: 'main'}, // tslint:disable-line no-invalid-template-strings
-        escape:   /\\./,
-        strend:   {match: '`', pop: 1},
-        const:    {match: /(?:[^$`]|\$(?!\{))+/, lineBreaks: true},
+        interp: { match: '${', push: 'main' }, // tslint:disable-line no-invalid-template-strings
+        escape: /\\./,
+        strend: { match: '`', pop: 1 },
+        const: { match: /(?:[^$`]|\$(?!\{))+/, lineBreaks: true },
     },
 });
 
+moo.compile({
+    myError: moo.error
+});
+
+moo.compile({
+    myError: { match: /[\$?`]/, error: true }
+});
+
+for (const here of lexer) {
+    const t: string | undefined = here.type;
+    const v: string = here.value;
+}
+
+const tokens: moo.Token[] = Array.from(lexer);
+
 lexer.reset('some line\n');
 const info = lexer.save();
 lexer.next();
diff --git a/types/moo/tsconfig.json b/types/moo/tsconfig.json
index 895fed83d5..e2659ef342 100644
--- a/types/moo/tsconfig.json
+++ b/types/moo/tsconfig.json
@@ -5,6 +5,7 @@
             "es6",
             "dom"
         ],
+        "target": "es6",
         "noImplicitAny": true,
         "noImplicitThis": true,
         "strictNullChecks": true,