Expose Typescript types in libSquoosh (#1142)

* Expose type declarations in libSquoosh npm package

* Add comment on why we remove the tsbuildinfo

* Fix PreprocessOptions type

Resize should require at least one of the width, height.
The other options are optional for all preprocessors

* Update libSquoosh README to reflect encode changes

I also removed requiring `await image.decoded` call before calling
preprocess or encode since they decode the image before the operation

libsquoosh/README.md

@@ -43,19 +43,15 @@ The returned `image` object is a representation of the original image, that you
 When an image has been ingested, you can start preprocessing it and encoding it to other formats. This example will resize the image and then encode it to a `.jpg` and `.jxl` image:
 
 ```js
-await image.decoded; //Wait until the image is decoded before running preprocessors.
-
 const preprocessOptions = {
   //When both width and height are specified, the image resized to specified size.
   resize: {
-    enabled: true,
     width: 100,
     height: 50,
   },
   /*
   //When either width or height is specified, the image resized to specified size keeping aspect ratio.
   resize: {
-    enabled: true,
     width: 100,
   }
   */
@@ -68,7 +64,7 @@ const encodeOptions = {
     quality: 90,
   },
 };
-await image.encode(encodeOptions);
+const result = await image.encode(encodeOptions);
 ```
 
 The default values for each option can be found in the [`codecs.ts`][codecs.ts] file under `defaultEncoderOptions`. Every unspecified value will use the default value specified there. _Better documentation is needed here._
@@ -92,7 +88,7 @@ When you have encoded an image, you normally want to write it to a file.
 This example takes an image that has been encoded as a `jpg` and writes it to a file:
 
 ```js
-const rawEncodedImage = (await image.encodedWith.mozjpeg).binary;
+const rawEncodedImage = image.encodedWith.mozjpeg.binary;
 
 fs.writeFile('/path/to/new/image.jpg', rawEncodedImage);
 ```
@@ -103,10 +99,7 @@ This example iterates through all encoded versions of the image and writes them
 const newImagePath = '/path/to/image.'; //extension is added automatically
 
 for (const encodedImage of Object.values(image.encodedWith)) {
-  fs.writeFile(
+  fs.writeFile(newImagePath + encodedImage.extension, encodedImage.binary);
-    newImagePath + (await encodedImage).extension,
-    (await encodedImage).binary,
-  );
 }
 ```
 
@@ -135,7 +128,7 @@ console.log(await image.decoded);
 Information about an encoded image can be found at `Image.encodedWith[encoderName]`. It looks something like this:
 
 ```js
-console.log(await image.encodedWith.jxl);
+console.log(image.encodedWith.jxl);
 // Returns:
 {
   optionsUsed: {

libsquoosh/lib/move-d-ts.js

@@ -0,0 +1,26 @@
+const fs = require('fs');
+const del = require('del');
+const path = require('path');
+
+const tsOutputDir = path.resolve('..', '.tmp', 'ts', 'libsquoosh');
+const tsOutputSourceDir = path.join(tsOutputDir, 'src');
+const buildDir = path.resolve('build');
+
+(async () => {
+  await del(path.join(buildDir, '*.d.ts'));
+  const files = await fs.promises.readdir(tsOutputSourceDir);
+
+  const movePromises = [];
+  for (const file of files) {
+    if (file.endsWith('d.ts') || file.endsWith('d.ts.map')) {
+      movePromises.push(
+        fs.promises.rename(
+          path.join(tsOutputSourceDir, file),
+          path.join(buildDir, file),
+        ),
+      );
+    }
+  }
+  // We need to remove `tsconfig.tsbuildinfo` otherwise TS does not emit unchanged `.d.ts` files
+  await del([path.join(tsOutputDir, 'tsconfig.tsbuildinfo')], { force: true });
+})();

libsquoosh/package.json

@@ -4,11 +4,12 @@
   "description": "A Node library for Squoosh",
   "public": true,
   "main": "./build/index.js",
+  "types": "./build/index.d.ts",
   "files": [
     "/build/*"
   ],
   "scripts": {
-    "build": "rollup -c"
+    "build": "rollup -c && node lib/move-d-ts.js"
   },
   "keywords": [],
   "author": "Google Chrome Developers <chromium-dev@google.com>",

libsquoosh/src/index.ts

@@ -22,9 +22,10 @@ type EncoderKey = keyof typeof encoders;
 type PreprocessorKey = keyof typeof preprocessors;
 
 type PreprocessOptions = {
-  resize?: ResizeOptions;
+  resize?: Partial<Omit<ResizeOptions, 'width' | 'height'>> &
-  quant?: QuantOptions;
+    (Pick<ResizeOptions, 'width'> | Pick<ResizeOptions, 'height'>);
-  rotate?: RotateOptions;
+  quant?: Partial<QuantOptions>;
+  rotate?: Partial<RotateOptions>;
 };
 type EncodeResult = {
   optionsUsed: object;

libsquoosh/tsconfig.json

@@ -3,7 +3,8 @@
   "compilerOptions": {
     "lib": ["esnext"],
     "types": ["node"],
-    "allowJs": true
+    "allowJs": true,
+    "declaration": true
   },
   "include": ["src/**/*", "../codecs/**/*"]
 }