Add TypeScript type declarations

Resolves #19

package.json

@@ -61,5 +61,8 @@
     "webpack-cli": "^3.1.2",
     "webpack-dev-server": "^3.1.10"
   },
-  "dependencies": {}
+  "dependencies": {},
+  "peerDependencies": {
+    "anylogger": "^0.18.0"
+  }
 }

ulog.d.ts

@@ -0,0 +1,90 @@
+import { BaseLevels, BaseLogger } from 'anylogger'
+
+type ValueOf<T> = T[keyof T]
+
+type LevelNames = BaseLevels & {
+    assert: 0
+    dir: 0
+    table: 0
+    time: 0
+    timeEnd: 0
+    verbose: 4
+    silly: 6
+}
+
+interface LevelConstants {
+    NONE: 0
+    ERROR: 1
+    WARN: 2
+    INFO: 3
+    LOG: 4
+    DEBUG: 5
+    TRACE: 6
+}
+
+export interface Logger extends BaseLogger<LevelNames>, LevelConstants {
+
+    readonly ulog: { version: string }
+
+    /**
+     * The log level of this logger.
+     */
+    level: LogLevel
+
+    assert(...args: any[]): void
+    dir(...args: any[]): void
+    table(...args: any[]): void
+    time(...args: any[]): void
+    timeEnd(...args: any[]): void
+    verbose(message?: any, ...args: any[]): void
+    silly(message?: any, ...args: any[]): void
+}
+
+export type LogLevel = ValueOf<LevelConstants>
+
+export type LogFormatter = (logger: Logger, method: keyof LevelNames, args: any[]) => void
+
+export type LoggerExtender = (logger: Logger, parent: Logger) => void
+
+export interface ULog extends LevelConstants {
+    /**
+     * Returns a logger with the specified name. If it doesn't exist yet,
+     * it will be created.
+     */
+    (name: string): Logger
+
+    /**
+     * The default log level.
+     */
+    level: LogLevel
+
+    /**
+     * Array of functions that will intercept calls to the logger functions to
+     * apply some formatting.
+     */
+    formats: LogFormatter[]
+
+    /**
+     * Array of functions that will be called with each new logger.
+     */
+    extends: LoggerExtender[]
+
+    /**
+     * Enables debug mode for the loggers listed in `names`.
+     */
+    enable(names: string): void
+
+    /**
+     * Tests whether the named logger is currently in debug mode.
+     */
+    enabled(name: string): true | undefined
+
+    /**
+     * Disables debug mode for all loggers.
+     */
+    disable(): void
+}
+
+declare const ulog: ULog
+
+export default ulog