Make code prettier

This updates ESLint and our shared eslint-config-openlayers to use Prettier.  Most formatting changes were automatically applied with this:

    npm run lint -- --fix

A few manual changes were required:

 * In `examples/offscreen-canvas.js`, the `//eslint-disable-line` comment needed to be moved to the appropriate line to disable the error about the `'worker-loader!./offscreen-canvas.worker.js'` import.
 * In `examples/webpack/exapmle-builder.js`, spaces could not be added after a couple `function`s for some reason.  While editing this, I reworked `ExampleBuilder` to be a class.
 * In `src/ol/format/WMSGetFeatureInfo.js`, the `// @ts-ignore` comment needed to be moved down one line so it applied to the `parsersNS` argument.

src/ol/interaction/DragAndDrop.js

@@ -3,13 +3,12 @@
  */
 // FIXME should handle all geo-referenced data, not just vector data
 
-import {TRUE} from '../functions.js';
-import {listen, unlistenByKey} from '../events.js';
 import Event from '../events/Event.js';
 import EventType from '../events/EventType.js';
 import Interaction from './Interaction.js';
+import {TRUE} from '../functions.js';
 import {get as getProjection} from '../proj.js';
-
+import {listen, unlistenByKey} from '../events.js';
 
 /**
  * @typedef {Object} Options
@@ -23,7 +22,6 @@ import {get as getProjection} from '../proj.js';
  * @property {HTMLElement} [target] The element that is used as the drop target, default is the viewport element.
  */
 
-
 /**
  * @enum {string}
  */
@@ -33,17 +31,15 @@ const DragAndDropEventType = {
    * @event DragAndDropEvent#addfeatures
    * @api
    */
-  ADD_FEATURES: 'addfeatures'
+  ADD_FEATURES: 'addfeatures',
 };
 
-
 /**
  * @classdesc
  * Events emitted by {@link module:ol/interaction/DragAndDrop~DragAndDrop} instances are instances
  * of this type.
  */
 class DragAndDropEvent extends Event {
-
   /**
    * @param {DragAndDropEventType} type Type.
    * @param {File} file File.
@@ -51,7 +47,6 @@ class DragAndDropEvent extends Event {
    * @param {import("../proj/Projection.js").default=} opt_projection Projection.
    */
   constructor(type, file, opt_features, opt_projection) {
-
     super(type);
 
     /**
@@ -74,12 +69,9 @@ class DragAndDropEvent extends Event {
      * @api
      */
     this.projection = opt_projection;
-
   }
-
 }
 
-
 /**
  * @classdesc
  * Handles input of vector data by drag and drop.
@@ -92,26 +84,27 @@ class DragAndDrop extends Interaction {
    * @param {Options=} opt_options Options.
    */
   constructor(opt_options) {
-
     const options = opt_options ? opt_options : {};
 
     super({
-      handleEvent: TRUE
+      handleEvent: TRUE,
     });
 
     /**
      * @private
      * @type {Array<typeof import("../format/Feature.js").default>}
      */
-    this.formatConstructors_ = options.formatConstructors ?
-      options.formatConstructors : [];
+    this.formatConstructors_ = options.formatConstructors
+      ? options.formatConstructors
+      : [];
 
     /**
      * @private
      * @type {import("../proj/Projection.js").default}
      */
-    this.projection_ = options.projection ?
-      getProjection(options.projection) : null;
+    this.projection_ = options.projection
+      ? getProjection(options.projection)
+      : null;
 
     /**
      * @private
@@ -130,7 +123,6 @@ class DragAndDrop extends Interaction {
      * @type {HTMLElement}
      */
     this.target = options.target ? options.target : null;
-
   }
 
   /**
@@ -152,7 +144,7 @@ class DragAndDrop extends Interaction {
     for (let i = 0, ii = formatConstructors.length; i < ii; ++i) {
       const format = new formatConstructors[i]();
       features = this.tryReadFeatures_(format, result, {
-        featureProjection: projection
+        featureProjection: projection,
       });
       if (features && features.length > 0) {
         break;
@@ -164,8 +156,12 @@ class DragAndDrop extends Interaction {
     }
     this.dispatchEvent(
       new DragAndDropEvent(
-        DragAndDropEventType.ADD_FEATURES, file,
-        features, projection));
+        DragAndDropEventType.ADD_FEATURES,
+        file,
+        features,
+        projection
+      )
+    );
   }
 
   /**
@@ -179,7 +175,7 @@ class DragAndDrop extends Interaction {
         listen(dropArea, EventType.DROP, handleDrop, this),
         listen(dropArea, EventType.DRAGENTER, handleStop, this),
         listen(dropArea, EventType.DRAGOVER, handleStop, this),
-        listen(dropArea, EventType.DROP, handleStop, this)
+        listen(dropArea, EventType.DROP, handleStop, this),
       ];
     }
   }
@@ -240,7 +236,6 @@ class DragAndDrop extends Interaction {
   }
 }
 
-
 /**
  * @param {DragEvent} event Event.
  * @this {DragAndDrop}
@@ -250,12 +245,14 @@ function handleDrop(event) {
   for (let i = 0, ii = files.length; i < ii; ++i) {
     const file = files.item(i);
     const reader = new FileReader();
-    reader.addEventListener(EventType.LOAD, this.handleResult_.bind(this, file));
+    reader.addEventListener(
+      EventType.LOAD,
+      this.handleResult_.bind(this, file)
+    );
     reader.readAsText(file);
   }
 }
 
-
 /**
  * @param {DragEvent} event Event.
  */
@@ -265,5 +262,4 @@ function handleStop(event) {
   event.dataTransfer.dropEffect = 'copy';
 }
 
-
 export default DragAndDrop;