diff --git a/types/strange/index.d.ts b/types/strange/index.d.ts
new file mode 100644
index 0000000000..8813c7de36
--- /dev/null
+++ b/types/strange/index.d.ts
@@ -0,0 +1,317 @@
+// Type definitions for strange 1.7
+// Project: https://github.com/moll/js-strange
+// Definitions by: Anjun Wang <https://github.com/wanganjun>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+export = Range;
+
+/**
+ * Create a new range object with the given begin and end endpoints.
+ * You can also pass a two character string for bounds. Defaults to` "[]"` for
+ * an all inclusive range.
+ *
+ * You can use any value for endpoints. `Null` is considered infinity for
+ * values that don't have a special infinity type like `Number` has `Infinity`.
+ *
+ * An empty range is one where either of the endpoints is `undefined`
+ * (like `new Range`) or a range with two equivalent, but exculsive endpoints
+ * (`new Range(5, 5, "[)")`).
+ *
+ * @example
+ * var Range = require("strange")
+ * new Range(10, 20) // => {begin: 10, end: 20, bounds: "[]"}
+ * new Range(new Date(2000, 5, 18), new Date(2000, 5, 22))
+ */
+declare const Range: RangeConstructor;
+
+interface RangeConstructor {
+    /**
+     *
+     * @param begin Range's beginning, or left endpoint.
+     * @param end Range's end, or right endpoint.
+     * @param bounds Range's bounds.
+     */
+    new <T extends Range.Endpoint>(begin?: T | null, end?: T | null, bounds?: Range.Bounds): Range<T>;
+
+    /**
+     *
+     * @param begin Range's beginning, or left endpoint.
+     * @param end Range's end, or right endpoint.
+     * @param bounds Range's bounds.
+     */
+    <T extends Range.Endpoint>(begin?: T | null, end?: T | null, bounds?: Range.Bounds): Range<T>;
+
+    /**
+     * Compares two range's beginnings.
+     * Returns `-1` if `a` begins before `b` begins, `0` if they're equal and `1`
+     * if `a` begins after `b`.
+     *
+     * @example
+     * Range.compareBeginToBegin(new Range(0, 10), new Range(5, 15)) // => -1
+     * Range.compareBeginToBegin(new Range(0, 10), new Range(0, 15)) // => 0
+     * Range.compareBeginToBegin(new Range(0, 10), new Range(0, 15, "()")) // => 1
+     */
+    compareBeginToBegin<U extends Range.Endpoint>(a: Range<U>, b: Range<U>): -1 | 0 | 1;
+
+    /**
+     * Compares the first range's beginning to the second's end.
+     * Returns `<0` if `a` begins before `b` ends, `0` if one starts where the other
+     * ends and `>1` if `a` begins after `b` ends.
+     *
+     * @example
+     * Range.compareBeginToEnd(new Range(0, 10), new Range(0, 5)) // => -1
+     * Range.compareBeginToEnd(new Range(0, 10), new Range(-10, 0)) // => 0
+     * Range.compareBeginToEnd(new Range(0, 10), new Range(-10, -5)) // => 1
+     */
+    compareBeginToEnd<U extends Range.Endpoint>(a: Range<U>, b: Range<U>): -1 | 0 | 1;
+
+    /**
+     * Compares two range's endings.
+     * Returns `-1` if `a` ends before `b` ends, `0` if they're equal and `1`
+     * if `a` ends after `b`.
+     *
+     * @example
+     * Range.compareEndToEnd(new Range(0, 10), new Range(5, 15)) // => -1
+     * Range.compareEndToEnd(new Range(0, 10), new Range(5, 10)) // => 0
+     * Range.compareEndToEnd(new Range(0, 10), new Range(5, 10, "()")) // => 1
+     */
+    compareEndToEnd<U extends Range.Endpoint>(a: Range<U>, b: Range<U>): -1 | 0 | 1;
+
+    /**
+     * Parses a string stringified by
+     * [`Range.prototype.toString`](#Range.prototype.toString).
+     *
+     * To have it also parse the endpoints to something other than a string, pass
+     * a function as the second argument.
+     *
+     * If you pass `Number` as the _parse_ function and the endpoints are
+     * unbounded, they'll be set to `Infinity` for easier computation.
+     *
+     * @example
+     * Range.parse("[a,z)") // => new Range("a", "z", "[)")
+     */
+    parse(range: string): Range<string>;
+
+    /**
+     * Parses a string stringified by
+     * [`Range.prototype.toString`](#Range.prototype.toString).
+     *
+     * To have it also parse the endpoints to something other than a string, pass
+     * a function as the second argument.
+     *
+     * If you pass `Number` as the _parse_ function and the endpoints are
+     * unbounded, they'll be set to `Infinity` for easier computation.
+     *
+     * @example
+     * Range.parse("[42,69]", Number) // => new Range(42, 69)
+     * Range.parse("[15,]", Number) // => new Range(15, Infinity)
+     * Range.parse("(,3.14]", Number) // => new Range(-Infinity, 3.14, "(]")
+     */
+    parse<U extends Range.Endpoint>(range: string, parse: (endpoint: string) => U): Range<U>;
+
+    /**
+     * Merges two ranges and returns a range that encompasses both of them.
+     * The ranges don't have to be intersecting.
+     *
+     * @example
+     * Range.union(new Range(0, 5), new Range(5, 10)) // => new Range(0, 10)
+     * Range.union(new Range(0, 10), new Range(5, 15)) // => new Range(0, 15)
+     *
+     * var a = new Range(-5, 0, "()")
+     * var b = new Range(5, 10)
+     * Range.union(a, b) // => new Range(-5, 10, "(]")
+     */
+    union<U extends Range.Endpoint>(a: Range<U>, b: Range<U>): Range<U>;
+
+    readonly prototype: Range<any>;
+}
+
+interface Range<T extends Range.Endpoint> {
+    /**
+     * Range's beginning, or left endpoint.
+     */
+    begin?: T | null;
+
+    /**
+     * Range's end, or right endpoint.
+     */
+    end?: T | null;
+
+    /**
+     * Range's bounds.
+     *
+     * Bounds signify whether the range includes or excludes that particular
+     * endpoint.
+     *
+     * Pair | Meaning
+     * -----|--------
+     * `()` | open
+     * `[]` | closed
+     * `[)` | left-closed, right-open
+     * `(]` | left-open, right-closed
+     *
+     * @example
+     * new Range(1, 5).bounds // => "[]"
+     * new Range(1, 5, "[)").bounds // => "[)"
+     */
+    bounds: Range.Bounds;
+
+    /**
+     * Compares this range's beginning with the given value.
+     * Returns `-1` if this range begins before the given value, `0` if they're
+     * equal and `1` if this range begins after the given value.
+     *
+     * `null` is considered to signify negative infinity for non-numeric range
+     * endpoints.
+     *
+     * @example
+     * new Range(0, 10).compareBegin(5) // => -1
+     * new Range(0, 10).compareBegin(0) // => 0
+     * new Range(5, 10).compareBegin(0) // => 1
+     * new Range(5, 10).compareBegin(null) // => 1
+     */
+    compareBegin(begin: T | null): -1 | 0 | 0;
+
+    /**
+     * Compares this range's end with the given value.
+     * Returns `-1` if this range ends before the given value, `0` if they're
+     * equal and `1` if this range ends after the given value.
+     *
+     * `null` is considered to signify positive infinity for non-numeric range
+     * endpoints.
+     *
+     * @example
+     * new Range(0, 10).compareEnd(5) // => -1
+     * new Range(0, 10).compareEnd(10) // => 0
+     * new Range(0, 5).compareEnd(10) // => 1
+     * new Range(0, 5).compareEnd(null) // => -1
+     */
+    compareEnd(end: T | null): -1 | 0 | 0;
+
+    /**
+     * Check whether the range is empty.
+     * An empty range is one where either of the endpoints is `undefined`
+     * (like `new Range`) or a range with two equivalent, but exculsive endpoints
+     * (`new Range(5, 5, "[)")`).
+     *
+     * Equivalence is checked by using the `<` operators, so value objects will be
+     * coerced into something comparable by JavaScript. That usually means calling
+     * the object's `valueOf` function.
+     *
+     * @example
+     * new Range().isEmpty() // => true
+     * new Range(5, 5, "[)").isEmpty() // => true
+     * new Range(1, 10).isEmpty() // => false
+     */
+    isEmpty(): boolean;
+
+    /**
+     * Check whether the range is bounded.
+     * A bounded range is one where neither endpoint is `null` or `Infinity`. An
+     * empty range is considered bounded.
+     *
+     * @example
+     * new Range().isBounded() // => true
+     * new Range(5, 5).isBounded() // => true
+     * new Range(null, new Date(2000, 5, 18)).isBounded() // => false
+     * new Range(0, Infinity).isBounded() // => false
+     * new Range(-Infinity, Infinity).isBounded() // => false
+     */
+    isBounded(): boolean;
+
+    /**
+     * @alias isBounded
+     */
+    isFinite(): boolean;
+
+    /**
+     * Check whether the range is unbounded.
+     * An unbounded range is one where either endpoint is `null` or `Infinity`. An
+     * empty range is not considered unbounded.
+     *
+     * @example
+     * new Range().isUnbounded() // => false
+     * new Range(5, 5).isUnbounded() // => false
+     * new Range(null, new Date(2000, 5, 18)).isUnbounded() // => true
+     * new Range(0, Infinity).isUnbounded() // => true
+     * new Range(-Infinity, Infinity).isUnbounded() // => true
+     */
+    isUnbounded(): boolean;
+
+    /**
+     * @alias isUnbounded
+     */
+    isInfinite(): boolean;
+
+    /**
+     * Check if a given value is contained within this range.
+     * Returns `true` or `false`.
+     *
+     * @example
+     * new Range(0, 10).contains(5) // => true
+     * new Range(0, 10).contains(10) // => true
+     * new Range(0, 10, "[)").contains(10) // => false
+     */
+    contains(value: T | null): boolean;
+
+    /**
+     * Check if this range intersects with another.
+     * Returns `true` or `false`.
+     *
+     * Ranges that have common points intersect. Ranges that are consecutive and
+     * with *inclusive* endpoints are also intersecting. An empty range will never
+     * intersect.
+     *
+     * @example
+     * new Range(0, 10).intersects(new Range(5, 7)) // => true
+     * new Range(0, 10).intersects(new Range(10, 20)) // => true
+     * new Range(0, 10, "[)").intersects(new Range(10, 20)) // => false
+     * new Range(0, 10).intersects(new Range(20, 30)) // => false
+     */
+    intersects(value: Range<T>): boolean;
+
+    /**
+     * Returns an array of the endpoints and bounds.
+     *
+     * Useful with [Egal.js](https://github.com/moll/js-egal) or other libraries
+     * that compare value objects by their `valueOf` output.
+     *
+     * @example
+     * new Range(1, 10, "[)").valueOf() // => [1, 10, "[)"]
+     */
+    valueOf(): [T | null | undefined, T | null | undefined, Range.Bounds];
+
+    /**
+     * Stringifies a range in `[a,b]` format.
+     *
+     * This happens to match the string format used by [PostgreSQL's range type
+     * format](http://www.postgresql.org/docs/9.4/static/rangetypes.html). You can
+     * therefore use stRange.js to parse and stringify ranges for your database.
+     *
+     * @example
+     * new Range(1, 5).toString() // => "[1,5]"
+     * new Range(1, 10, "[)").toString() // => "[1,10)"
+     */
+    toString(): string;
+
+    /**
+     * Stringifies the range when passing it to `JSON.stringify`.
+     * This way you don't need to manually call `toString` when stringifying.
+     *
+     * @example
+     * JSON.stringify(new Range(1, 10)) // "\"[1,10]\""
+     *
+     * @alias toString
+     */
+    toJSON(): string;
+
+    /**
+     * @alias toJSON
+     */
+    inspect(): string;
+}
+
+declare namespace Range {
+    type Endpoint = Date | number | string;
+    type Bounds = '()' | '[]' | '[)' | '(]';
+}
diff --git a/types/strange/strange-tests.ts b/types/strange/strange-tests.ts
new file mode 100644
index 0000000000..432911d0d4
--- /dev/null
+++ b/types/strange/strange-tests.ts
@@ -0,0 +1,117 @@
+import * as Range from 'strange';
+import * as RangeTree from 'strange/tree';
+
+{
+    new Range();
+    new Range(1, Infinity);
+    new Range(null, 10);
+    new Range(undefined, 10);
+    new Range(1, 10, '[]');
+    new Range(-Infinity, null, '[]');
+    new Range(1, undefined, '[]');
+
+    Range();
+    Range(1, Infinity);
+    Range(null, 10);
+    Range(undefined, 10);
+    Range(1, 10, '[]');
+    Range(-Infinity, null, '[]');
+    Range(1, undefined, '[]');
+
+    new Range(new Date(2000, 5, 18), new Date(2000, 5, 22));
+
+    new Range(0, 10).begin;
+    new Range(0, 10).end;
+    new Range(0, 10).bounds;
+
+    new Range<number>(0, 10).compareBegin(5); // => -1
+    new Range<number>(0, 10).compareBegin(0); // => 0
+    new Range<number>(5, 10).compareBegin(0); // => 1
+    new Range(5, 10).compareBegin(null); // => 1
+
+    new Range<number>(0, 10).compareEnd(5); // => -1
+    new Range<number>(0, 10).compareEnd(10); // => 0
+    new Range<number>(0, 5).compareEnd(10); // => 1
+    new Range(0, 5).compareEnd(null); // => -1
+
+    new Range().isEmpty(); // => true
+    new Range(5, 5, "[)").isEmpty(); // => true
+    new Range(1, 10).isEmpty(); // => false
+
+    new Range().isBounded(); // => true
+    new Range(5, 5).isBounded(); // => true
+    new Range(null, new Date(2000, 5, 18)).isBounded(); // => false
+    new Range(0, Infinity).isBounded(); // => false
+    new Range(-Infinity, Infinity).isBounded(); // => false
+
+    new Range().isFinite(); // => true
+    new Range(5, 5).isFinite(); // => true
+    new Range(null, new Date(2000, 5, 18)).isFinite(); // => false
+    new Range(0, Infinity).isFinite(); // => false
+    new Range(-Infinity, Infinity).isFinite(); // => false
+
+    new Range().isUnbounded(); // => false
+    new Range(5, 5).isUnbounded(); // => false
+    new Range(null, new Date(2000, 5, 18)).isUnbounded(); // => true
+    new Range(0, Infinity).isUnbounded(); // => true
+    new Range(-Infinity, Infinity).isUnbounded(); // => true
+
+    new Range().isInfinite(); // => false
+    new Range(5, 5).isInfinite(); // => false
+    new Range(null, new Date(2000, 5, 18)).isInfinite(); // => true
+    new Range(0, Infinity).isInfinite(); // => true
+    new Range(-Infinity, Infinity).isInfinite(); // => true
+
+    new Range<number>(0, 10).contains(5); // => true
+    new Range(0, 10).contains(10); // => true
+    new Range(0, 10, "[)").contains(10); // => false
+
+    new Range<number>(0, 10).intersects(new Range(5, 7)); // => true
+    new Range<number>(0, 10).intersects(new Range(10, 20)); // => true
+    new Range<number>(0, 10, "[)").intersects(new Range(10, 20)); // => false
+    new Range<number>(0, 10).intersects(new Range(20, 30)); // => false
+
+    new Range(1, 10, "[)").valueOf(); // => [1, 10, "[)"]
+
+    new Range(1, 5).toString(); // => "[1,5]"
+    new Range(1, 10, "[)").toString(); // => "[1,10)"
+
+    JSON.stringify(new Range(1, 10)); // "\"[1,10]\""
+    new Range(1, 10).toJSON(); // "\"[1,10]\""
+    new Range(1, 10).inspect(); // "\"[1,10]\""
+
+    Range.compareBeginToBegin(new Range(0, 10), new Range(5, 15)); // => -1
+    Range.compareBeginToBegin(new Range(0, 10), new Range(0, 15)); // => 0
+    Range.compareBeginToBegin(new Range(0, 10), new Range(0, 15, "()")); // => 1
+
+    Range.compareBeginToEnd(new Range(0, 10), new Range(0, 5)); // => -1
+    Range.compareBeginToEnd(new Range(0, 10), new Range(-10, 0)); // => 0
+    Range.compareBeginToEnd(new Range(0, 10), new Range(-10, -5)); // => 1
+
+    Range.compareEndToEnd(new Range(0, 10), new Range(5, 15)); // => -1
+    Range.compareEndToEnd(new Range(0, 10), new Range(5, 10)); // => 0
+    Range.compareEndToEnd(new Range(0, 10), new Range(5, 10, "()")); // => 1
+
+    Range.parse("[a,z)"); // => new Range("a", "z", "[)")
+    Range.parse("[42,69]", Number); // => new Range(42, 69)
+    Range.parse("[15,]", Number); // => new Range(15, Infinity)
+    Range.parse("(,3.14]", Number); // => new Range(-Infinity, 3.14, "(]")
+
+    Range.union(new Range(0, 5), new Range(5, 10)); // => new Range(0, 10)
+    Range.union(new Range(0, 10), new Range(5, 15)); // => new Range(0, 15)
+
+    const a = new Range(-5, 0, "()");
+    const b = new Range(5, 10);
+    Range.union(a, b); // => new Range(-5, 10, "(]")
+}
+
+{
+    const left = new RangeTree([new Range(-5, 0)]);
+    const right = new RangeTree([new Range(5, 10)]);
+    const root = new RangeTree<number>([new Range(0, 5), new Range(0, 10)], left, right);
+    root.search(7); // => [new Range(0, 10), new Range(5, 10)]
+    root.search(new Range(8, 9)); // => [new Range(5, 10), new Range(0, 10)]
+
+    const ranges = [new Range(0, 10), new Range(20, 30), new Range(40, 50)];
+    RangeTree.from<number>(ranges).search(42); // => [new Range(40, 50)]
+}
diff --git a/types/strange/tree.d.ts b/types/strange/tree.d.ts
new file mode 100644
index 0000000000..f768a3c727
--- /dev/null
+++ b/types/strange/tree.d.ts
@@ -0,0 +1,59 @@
+import Range = require('./index');
+
+export = RangeTree;
+
+/**
+ * Create an interval tree node.
+ *
+ * For creating a binary search tree out of an array of ranges, you might want
+ * to use [`RangeTree.from`](#RangeTree.from).
+ *
+ * @example
+ * var RangeTree = require("strange/tree")
+ * var left = new RangeTree([new Range(-5, 0)])
+ * var right = new RangeTree([new Range(5, 10)])
+ * var root = new RangeTree([new Range(0, 5), new Range(0, 10)], left, right)
+ * root.search(7) // => [new Range(0, 10), new Range(5, 10)]
+ */
+declare class RangeTree<T extends Date | number | string> {
+    /**
+     * Create an interval tree (implemented as an augmented binary search tree)
+     * from an array of ranges.
+     * Returns a [`RangeTree`](#RangeTree) you can search on.
+     *
+     * If you need to relate the found ranges to other data, add some properties
+     * directly to every range _or_ use JavaScript's `Map` or `WeakMap` to relate
+     * extra data to those range instances.
+     *
+     * @example
+     * var ranges = [new Range(0, 10), new Range(20, 30), new Range(40, 50)]
+     * RangeTree.from(ranges).search(42) // => [new Range(40, 50)]
+     */
+    static from<U extends Date | number | string>(ranges: Array<Range<U>>): RangeTree<U>;
+
+    /**
+     * Ranges of current tree node.
+     */
+    private keys: Array<Range<T>>;
+    private left: RangeTree<T> | null;
+    private right: RangeTree<T> | null;
+
+    constructor(ranges: Range<T> | Array<Range<T>>, left?: RangeTree<T> | null, right?: RangeTree<T> | null);
+
+    /**
+     * Search for ranges that include the given value or, given a range, intersect
+     * with it.
+     * Returns an array of matches or an empty one if no range contained or
+     * intersected with the given value.
+     *
+     * @example
+     * var tree = RangeTree.from([new Range(40, 50)])
+     * tree.search(42) // => [new Range(40, 50)]
+     * tree.search(13) // => []
+     * tree.search(new Range(30, 42)) // => [new Range(40, 50)]
+     */
+    search(valueOrRange: null | T | Range<T>): Array<Range<T>>;
+}
+
+declare namespace RangeTree {
+}
diff --git a/types/strange/tsconfig.json b/types/strange/tsconfig.json
new file mode 100644
index 0000000000..5267392b24
--- /dev/null
+++ b/types/strange/tsconfig.json
@@ -0,0 +1,24 @@
+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "lib": [
+            "es6"
+        ],
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictNullChecks": true,
+        "strictFunctionTypes": true,
+        "baseUrl": "../",
+        "typeRoots": [
+            "../"
+        ],
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true
+    },
+    "files": [
+        "index.d.ts",
+        "strange-tests.ts",
+        "tree.d.ts"
+    ]
+}
diff --git a/types/strange/tslint.json b/types/strange/tslint.json
new file mode 100644
index 0000000000..f93cf8562a
--- /dev/null
+++ b/types/strange/tslint.json
@@ -0,0 +1,3 @@
+{
+    "extends": "dtslint/dt.json"
+}