Add lint to CI and fix errors (#853)

Adds lint to CI and fixes errors.
I'm not sure I'm fully proud of all the solutions there.
But there's no lint issues and the lint is being checked as part of the
CI.

---------

Co-authored-by: Yuri Astrakhan <yuriastrakhan@gmail.com>

src/components/LayerEditor.tsx

@@ -1,4 +1,4 @@
-import React from 'react'
+import React, {type JSX} from 'react'
 import PropTypes from 'prop-types'
 import { Wrapper, Button, Menu, MenuItem } from 'react-aria-menubutton'
 import {Accordion} from 'react-accessible-accordion';
@@ -150,87 +150,87 @@ export default class LayerEditor extends React.Component<LayerEditorProps, Layer
 
     let sourceLayerIds;
     const layer = this.props.layer as Exclude<LayerSpecification, BackgroundLayerSpecification>;
-    if(this.props.sources.hasOwnProperty(layer.source)) {
+    if(Object.prototype.hasOwnProperty.call(this.props.sources, layer.source)) {
       sourceLayerIds = (this.props.sources[layer.source] as any).layers;
     }
 
     switch(type) {
-      case 'layer': return <div>
-        <FieldId
-          value={this.props.layer.id}
-          wdKey="layer-editor.layer-id"
-          error={errorData.id}
-          onChange={newId => this.props.onLayerIdChange(this.props.layerIndex, this.props.layer.id, newId)}
-        />
-        <FieldType
-          disabled={true}
-          error={errorData.type}
-          value={this.props.layer.type}
-          onChange={newType => this.props.onLayerChanged(
-            this.props.layerIndex,
-            changeType(this.props.layer, newType)
-          )}
-        />
-        {this.props.layer.type !== 'background' && <FieldSource
-          error={errorData.source}
-          sourceIds={Object.keys(this.props.sources!)}
-          value={this.props.layer.source}
-          onChange={v => this.changeProperty(null, 'source', v)}
-        />
-        }
-        {['background', 'raster', 'hillshade', 'heatmap'].indexOf(this.props.layer.type) < 0 &&
+    case 'layer': return <div>
+      <FieldId
+        value={this.props.layer.id}
+        wdKey="layer-editor.layer-id"
+        error={errorData.id}
+        onChange={newId => this.props.onLayerIdChange(this.props.layerIndex, this.props.layer.id, newId)}
+      />
+      <FieldType
+        disabled={true}
+        error={errorData.type}
+        value={this.props.layer.type}
+        onChange={newType => this.props.onLayerChanged(
+          this.props.layerIndex,
+          changeType(this.props.layer, newType)
+        )}
+      />
+      {this.props.layer.type !== 'background' && <FieldSource
+        error={errorData.source}
+        sourceIds={Object.keys(this.props.sources!)}
+        value={this.props.layer.source}
+        onChange={v => this.changeProperty(null, 'source', v)}
+      />
+      }
+      {['background', 'raster', 'hillshade', 'heatmap'].indexOf(this.props.layer.type) < 0 &&
         <FieldSourceLayer
           error={errorData['source-layer']}
           sourceLayerIds={sourceLayerIds}
           value={(this.props.layer as any)['source-layer']}
           onChange={v => this.changeProperty(null, 'source-layer', v)}
         />
-        }
-        <FieldMinZoom
-          error={errorData.minzoom}
-          value={this.props.layer.minzoom}
-          onChange={v => this.changeProperty(null, 'minzoom', v)}
-        />
-        <FieldMaxZoom
-          error={errorData.maxzoom}
-          value={this.props.layer.maxzoom}
-          onChange={v => this.changeProperty(null, 'maxzoom', v)}
-        />
-        <FieldComment
-          error={errorData.comment}
-          value={comment}
-          onChange={v => this.changeProperty('metadata', 'maputnik:comment', v == ""  ? undefined : v)}
-        />
-      </div>
-      case 'filter': return <div>
-        <div className="maputnik-filter-editor-wrapper">
-          <FilterEditor
-            errors={errorData}
-            filter={(this.props.layer as any).filter}
-            properties={this.props.vectorLayers[(this.props.layer as any)['source-layer']]}
-            onChange={f => this.changeProperty(null, 'filter', f)}
-          />
-        </div>
-      </div>
-      case 'properties':
-        return <PropertyGroup
+      }
+      <FieldMinZoom
+        error={errorData.minzoom}
+        value={this.props.layer.minzoom}
+        onChange={v => this.changeProperty(null, 'minzoom', v)}
+      />
+      <FieldMaxZoom
+        error={errorData.maxzoom}
+        value={this.props.layer.maxzoom}
+        onChange={v => this.changeProperty(null, 'maxzoom', v)}
+      />
+      <FieldComment
+        error={errorData.comment}
+        value={comment}
+        onChange={v => this.changeProperty('metadata', 'maputnik:comment', v == ""  ? undefined : v)}
+      />
+    </div>
+    case 'filter': return <div>
+      <div className="maputnik-filter-editor-wrapper">
+        <FilterEditor
           errors={errorData}
-          layer={this.props.layer}
-          groupFields={fields!}
-          spec={this.props.spec}
-          onChange={this.changeProperty.bind(this)}
+          filter={(this.props.layer as any).filter}
+          properties={this.props.vectorLayers[(this.props.layer as any)['source-layer']]}
+          onChange={f => this.changeProperty(null, 'filter', f)}
         />
-      case 'jsoneditor':
-        return <FieldJson
-          layer={this.props.layer}
-          onChange={(layer) => {
-            this.props.onLayerChanged(
-              this.props.layerIndex,
-              layer
-            );
-          }}
-        />
-        default: return <></>
+      </div>
+    </div>
+    case 'properties':
+      return <PropertyGroup
+        errors={errorData}
+        layer={this.props.layer}
+        groupFields={fields!}
+        spec={this.props.spec}
+        onChange={this.changeProperty.bind(this)}
+      />
+    case 'jsoneditor':
+      return <FieldJson
+        layer={this.props.layer}
+        onChange={(layer) => {
+          this.props.onLayerChanged(
+            this.props.layerIndex,
+            layer
+          );
+        }}
+      />
+    default: return <></>
     }
   }