Add a new base element for Inputs that extends LitElement instead of …

…Polymer

package.json

@@ -29,6 +29,7 @@
     "dr-niels-sortable-list": "git://github.com/DrNiels/sortable-list.git#master",
     "ethiopian-date": "0.0.6",
     "image-blob-reduce": "^3.0.1",
+    "lit": "^2.2.0",
     "lit-element": "^2.3.1",
     "moment": "^2.24.0",
     "redux": "^4.0.0",

tangy-input-lit-base.js

@@ -0,0 +1,26 @@
+import { LitElement } from 'lit';
+
+export class TangyInputLitBase extends LitElement {
+
+  connectedCallback() {
+    super.connectedCallback()
+    this._initialProps = super.getProps()
+  }
+
+  getModProps() {
+    const initialProps = this._initialProps
+    const currentProps = super.getProps()
+    const modifiedProps = {}
+    for (const key of Object.keys(currentProps)) {
+      if (typeof currentProps[key] === 'object' || initialProps[key] !== currentProps[key]) {
+        modifiedProps[key] = currentProps[key]
+      }
+    }
+    return {
+      name: this.getAttribute('name'),
+      value: this.value,
+      ...modifiedProps
+    }
+  }
+
+}