Add Flow type definition for the "debug" library

Reviewed By: rafeca

Differential Revision: D6706956

fbshipit-source-id: 6192beb439440ef36fd74645805922daf7318530

flow-typed/debug.js.flow

@@ -0,0 +1,43 @@
+/**
+ * Copyright (c) 2013-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @flow
+ * @format
+ */
+
+// https://github.com/visionmedia/debug
+// https://www.npmjs.com/package/debug
+
+declare module 'debug' {
+  //declare export default (string) => (?mixed, ?mixed) => void
+  // declare export default (namespace: string) => void
+  // note: this is NOT a default export! There is no default property.
+  declare module.exports: (namespace: string) => (...Array<mixed>) => void;
+
+  // Unable to type the remaining API:
+  // "Found both `declare module.exports` and `declare export` in
+  // the same module. Modules can only have 1 since they are either
+  // an ES module xor they are a CommonJS module."
+  // And you can't call a union type so let's ignore the rest of the API.
+  // Note that we only use the main debug export anyways.
+
+  // declare export function coerce(mixed): void;
+  // declare export var colors: Array<number>;
+  // declare export function disable(namespace: string): void;
+  // declare export function enable(namespace: string): void;
+  // declare export function enabled(namespace: string): boolean;
+  // declare export function formatArgs(mixed): mixed;
+  // declare export var formatters: Array<(mixed) => void>;
+  // declare export function humanize(mixed): string;
+  // declare export function load(): string;
+  // declare export function log(mixed): void;
+  // declare export var names: Array<string>;
+  // declare export function save(namespaces: string): void;
+  // declare export var skips: Array<RegExp>;
+  // declare export function useColors(): boolean;
+}