Docs: add/correct some operation examples

docs/api-operation.md

@@ -53,6 +53,12 @@ The use of `flip` implies the removal of the EXIF `Orientation` tag, if any.
 
 *   `flip` **[Boolean][6]**  (optional, default `true`)
 
+### Examples
+
+```javascript
+const output = await sharp(input).flip().toBuffer();
+```
+
 Returns **Sharp** 
 
 ## flop
@@ -64,6 +70,12 @@ The use of `flop` implies the removal of the EXIF `Orientation` tag, if any.
 
 *   `flop` **[Boolean][6]**  (optional, default `true`)
 
+### Examples
+
+```javascript
+const output = await sharp(input).flop().toBuffer();
+```
+
 Returns **Sharp** 
 
 ## affine
@@ -178,7 +190,15 @@ When used without parameters the default window is 3x3.
 
 *   `size` **[number][1]** square mask size: size x size (optional, default `3`)
 
-<!---->
+### Examples
+
+```javascript
+const output = await sharp(input).median().toBuffer();
+```
+
+```javascript
+const output = await sharp(input).median(5).toBuffer();
+```
 
 *   Throws **[Error][5]** Invalid parameters
 
@@ -277,6 +297,12 @@ Enhance output image contrast by stretching its luminance to cover the full dyna
 
 *   `normalise` **[Boolean][6]**  (optional, default `true`)
 
+### Examples
+
+```javascript
+const output = await sharp(input).normalise().toBuffer();
+```
+
 Returns **Sharp** 
 
 ## normalize
@@ -287,6 +313,12 @@ Alternative spelling of normalise.
 
 *   `normalize` **[Boolean][6]**  (optional, default `true`)
 
+### Examples
+
+```javascript
+const output = await sharp(input).normalize().toBuffer();
+```
+
 Returns **Sharp** 
 
 ## clahe
@@ -306,7 +338,16 @@ This will, in general, enhance the clarity of the image by bringing out darker d
         cumulative histogram. A value of 0 disables contrast limiting. Valid values
         are integers in the range 0-100 (inclusive) (optional, default `3`)
 
-<!---->
+### Examples
+
+```javascript
+const output = await sharp(input)
+  .clahe({
+    width: 3,
+    height: 3,
+  })
+  .toBuffer();
+```
 
 *   Throws **[Error][5]** Invalid parameters
 
@@ -458,28 +499,41 @@ brightness is multiplicative whereas lightness is additive.
 ### Examples
 
 ```javascript
-sharp(input)
+// increase brightness by a factor of 2
+const output = await sharp(input)
   .modulate({
-    brightness: 2 // increase brightness by a factor of 2
-  });
+    brightness: 2
+  })
+  .toBuffer();
+```
 
-sharp(input)
+```javascript
+// hue-rotate by 180 degrees
+const output = await sharp(input)
   .modulate({
-    hue: 180 // hue-rotate by 180 degrees
-  });
+    hue: 180
+  })
+  .toBuffer();
+```
 
-sharp(input)
+```javascript
+// increase lightness by +50
+const output = await sharp(input)
   .modulate({
-    lightness: 50 // increase lightness by +50
-  });
+    lightness: 50
+  })
+  .toBuffer();
+```
 
+```javascript
 // decreate brightness and saturation while also hue-rotating by 90 degrees
-sharp(input)
+const output = await sharp(input)
   .modulate({
     brightness: 0.5,
     saturation: 0.5,
-    hue: 90
-  });
+    hue: 90,
+  })
+  .toBuffer();
 ```
 
 Returns **Sharp** 

lib/operation.js

@@ -63,6 +63,10 @@ function rotate (angle, options) {
 /**
  * Flip the image about the vertical Y axis. This always occurs after rotation, if any.
  * The use of `flip` implies the removal of the EXIF `Orientation` tag, if any.
+ *
+ * @example
+ * const output = await sharp(input).flip().toBuffer();
+ *
  * @param {Boolean} [flip=true]
  * @returns {Sharp}
  */
@@ -74,6 +78,10 @@ function flip (flip) {
 /**
  * Flop the image about the horizontal X axis. This always occurs after rotation, if any.
  * The use of `flop` implies the removal of the EXIF `Orientation` tag, if any.
+ *
+ * @example
+ * const output = await sharp(input).flop().toBuffer();
+ *
  * @param {Boolean} [flop=true]
  * @returns {Sharp}
  */
@@ -291,6 +299,13 @@ function sharpen (options) {
 /**
  * Apply median filter.
  * When used without parameters the default window is 3x3.
+ *
+ * @example
+ * const output = await sharp(input).median().toBuffer();
+ *
+ * @example
+ * const output = await sharp(input).median(5).toBuffer();
+ *
  * @param {number} [size=3] square mask size: size x size
  * @returns {Sharp}
  * @throws {Error} Invalid parameters
@@ -421,6 +436,10 @@ function negate (options) {
 
 /**
  * Enhance output image contrast by stretching its luminance to cover the full dynamic range.
+ *
+ * @example
+ * const output = await sharp(input).normalise().toBuffer();
+ *
  * @param {Boolean} [normalise=true]
  * @returns {Sharp}
  */
@@ -431,6 +450,10 @@ function normalise (normalise) {
 
 /**
  * Alternative spelling of normalise.
+ *
+ * @example
+ * const output = await sharp(input).normalize().toBuffer();
+ *
  * @param {Boolean} [normalize=true]
  * @returns {Sharp}
  */
@@ -446,6 +469,14 @@ function normalize (normalize) {
  *
  * @since 0.28.3
  *
+ * @example
+ * const output = await sharp(input)
+ *   .clahe({
+ *     width: 3,
+ *     height: 3,
+ *   })
+ *   .toBuffer();
+ *
  * @param {Object} options
  * @param {number} options.width - integer width of the region in pixels.
  * @param {number} options.height - integer height of the region in pixels.
@@ -655,28 +686,38 @@ function recomb (inputMatrix) {
  * @since 0.22.1
  *
  * @example
- * sharp(input)
+ * // increase brightness by a factor of 2
+ * const output = await sharp(input)
  *   .modulate({
- *     brightness: 2 // increase brightness by a factor of 2
- *   });
+ *     brightness: 2
+ *   })
+ *   .toBuffer();
  *
- * sharp(input)
+ * @example
+ * // hue-rotate by 180 degrees
+ * const output = await sharp(input)
  *   .modulate({
- *     hue: 180 // hue-rotate by 180 degrees
- *   });
+ *     hue: 180
+ *   })
+ *   .toBuffer();
  *
- * sharp(input)
+ * @example
+ * // increase lightness by +50
+ * const output = await sharp(input)
  *   .modulate({
- *     lightness: 50 // increase lightness by +50
- *   });
+ *     lightness: 50
+ *   })
+ *   .toBuffer();
  *
+ * @example
  * // decreate brightness and saturation while also hue-rotating by 90 degrees
- * sharp(input)
+ * const output = await sharp(input)
  *   .modulate({
  *     brightness: 0.5,
  *     saturation: 0.5,
- *     hue: 90
- *   });
+ *     hue: 90,
+ *   })
+ *   .toBuffer();
  *
  * @param {Object} [options]
  * @param {number} [options.brightness] Brightness multiplier