add TypeScript definition

src/index.d.ts

@@ -0,0 +1,105 @@
+type FSMethodNames = { [K in keyof typeof FS]: (typeof FS)[K] extends (...args: any[]) => any ? K : never }[keyof typeof FS];
+type FSMethodArgs = { [K in FSMethodNames]: Parameters<(typeof FS)[K]> };
+type FSMethodReturn = { [K in FSMethodNames]: ReturnType<(typeof FS)[K]> };
+
+type LogCallback = (logParams: { type: string; message: string }) => any;
+type ProgressCallback = (progressParams: { ratio: number }) => any;
+
+export interface CreateFFmpegOptions {
+    /** path for ffmpeg-core.js script */
+    corePath?: string;
+    /** a boolean to turn on all logs, default is false */
+    log?: boolean;
+    /** a function to get log messages, a quick example is ({ message }) => console.log(message) */
+    logger?: LogCallback;
+    /** a function to trace the progress, a quick example is p => console.log(p) */
+    progress?: ProgressCallback;
+}
+
+export interface FFmpeg {
+    /*
+     * Load ffmpeg.wasm-core script.
+     * In browser environment, the ffmpeg.wasm-core script is fetch from
+     * CDN and can be assign to a local path by assigning `corePath`.
+     * In node environment, we use dynamic require and the default `corePath`
+     * is `$ffmpeg/core`.
+     *
+     * Typically the load() func might take few seconds to minutes to complete,
+     * better to do it as early as possible.
+     *
+     */
+    load(): Promise<void>;
+    /*
+     * Determine whether the Core is loaded.
+     */
+    isLoaded(): boolean;
+    /*
+     * Run ffmpeg command.
+     * This is the major function in ffmpeg.wasm, you can just imagine it
+     * as ffmpeg native cli and what you need to pass is the same.
+     *
+     * For example, you can convert native command below:
+     *
+     * ```
+     * $ ffmpeg -i video.avi -c:v libx264 video.mp4
+     * ```
+     *
+     * To
+     *
+     * ```
+     * await ffmpeg.run('-i', 'video.avi', '-c:v', 'libx264', 'video.mp4');
+     * ```
+     *
+     */
+    run(...args: string[]): Promise<void>;
+    /*
+     * Run FS operations.
+     * For input/output file of ffmpeg.wasm, it is required to save them to MEMFS
+     * first so that ffmpeg.wasm is able to consume them. Here we rely on the FS
+     * methods provided by Emscripten.
+     *
+     * Common methods to use are:
+     * ffmpeg.FS('writeFile', 'video.avi', new Uint8Array(...)): writeFile writes
+     * data to MEMFS. You need to use Uint8Array for binary data.
+     * ffmpeg.FS('readFile', 'video.mp4'): readFile from MEMFS.
+     * ffmpeg.FS('unlink', 'video.map'): delete file from MEMFS.
+     *
+     * For more info, check https://emscripten.org/docs/api_reference/Filesystem-API.html
+     *
+     */
+    FS<Method extends FSMethodNames>(method: Method, ...args: FSMethodArgs[Method]): FSMethodReturn[Method];
+    setProgress(progress: ProgressCallback): void;
+    setLogger(log: LogCallback): void;
+    setLogging(logging: boolean): void;
+}
+
+/*
+ * Create ffmpeg instance.
+ * Each ffmpeg instance owns an isolated MEMFS and works
+ * independently.
+ *
+ * For example:
+ *
+ * ```
+ * const ffmpeg = createFFmpeg({
+ *  log: true,
+ *  logger: () => {},
+ *  progress: () => {},
+ *  corePath: '',
+ * })
+ * ```
+ *
+ * For the usage of these four arguments, check config.js
+ *
+ */
+export function createFFmpeg(options?: CreateFFmpegOptions): FFmpeg;
+/*
+ * Helper function for fetching files from various resource.
+ * Sometimes the video/audio file you want to process may located
+ * in a remote URL and somewhere in your local file system.
+ *
+ * This helper function helps you to fetch to file and return an
+ * Uint8Array variable for ffmpeg.wasm to consume.
+ *
+ */
+export function fetchFile(data: string | Buffer | Blob | File): Uint8Array;