fix: update typescript to latest 3 and fix errors

package.json

@@ -77,7 +77,7 @@
     "rimraf": "^2.6.3",
     "rollup": "^2.0.0",
     "sinon": "^7.2.2",
-    "typescript": "^3.8.3",
+    "typescript": "3.9.7",
     "web-component-analyzer": "^1.0.3",
     "webpack-merge": "^4.1.5",
     "whatwg-fetch": "^3.0.0"

packages/accordion/src/LionAccordion.js

@@ -333,7 +333,7 @@ export class LionAccordion extends LitElement {
     if (!(this.__store && this.__store[this.focusedIndex])) {
       return;
     }
-    const previousInvoker = /** @type {HTMLElement | null} */ (Array.from(this.children).find(
+    const previousInvoker = /** @type {HTMLElement | undefined} */ (Array.from(this.children).find(
       child => child.slot === 'invoker' && child.firstElementChild?.hasAttribute('focused'),
     ));
     if (previousInvoker) {

packages/form-core/src/validate/LionValidationFeedback.js

@@ -2,7 +2,7 @@ import { html, LitElement } from '@lion/core';
 
 /**
  * @typedef {import('../validate/Validator').Validator} Validator
- *
+ * @typedef {import('@lion/core').TemplateResult} TemplateResult
  * @typedef {Object} messageMap
  * @property {string | Node} message
  * @property {string} type
@@ -23,7 +23,7 @@ export class LionValidationFeedback extends LitElement {
   /**
    * @overridable
    * @param {Object} opts
-   * @param {string | Node} opts.message message or feedback node
+   * @param {string | Node | TemplateResult } opts.message message or feedback node or TemplateResult
    * @param {string} [opts.type]
    * @param {Validator} [opts.validator]
    */

packages/input-amount/src/LionInputAmount.js

@@ -9,7 +9,6 @@ import { parseAmount } from './parsers.js';
  * `LionInputAmount` is a class for an amount custom form element (`<lion-input-amount>`).
  *
  * @customElement lion-input-amount
- * @extends {LionInput}
  */
 // @ts-expect-error false positive for incompatible static get properties. Lit-element merges super properties already for you.
 export class LionInputAmount extends LocalizeMixin(LionInput) {
@@ -43,7 +42,7 @@ export class LionInputAmount extends LocalizeMixin(LionInput) {
           el.textContent = this.__currencyLabel;
           return el;
         }
-        return null;
+        return undefined;
       },
     };
   }

packages/input-datepicker/src/LionInputDatepicker.js

@@ -70,7 +70,7 @@ export class LionInputDatepicker extends ScopedElementsMixin(
             eventContext: this,
           },
         );
-        return renderParent.firstElementChild;
+        return /** @type {HTMLElement} */ (renderParent.firstElementChild);
       },
     };
   }

packages/input-range/src/LionInputRange.js

@@ -53,6 +53,10 @@ export class LionInputRange extends LocalizeMixin(LionInput) {
     `;
   }
 
+  get _inputNode() {
+    return /** @type {HTMLInputElement} */ (super._inputNode);
+  }
+
   constructor() {
     super();
     this.min = Infinity;

packages/input-stepper/src/LionInputStepper.js

@@ -7,7 +7,6 @@ import { IsNumber, MinNumber, MaxNumber } from '@lion/form-core';
  *
  * @customElement lion-input-stepper
  */
-// @ts-expect-error false positive for incompatible static get properties. Lit-element merges super properties already for you.
 export class LionInputStepper extends LionInput {
   static get styles() {
     return [
@@ -44,6 +43,10 @@ export class LionInputStepper extends LionInput {
     return parseFloat(this.value) || 0;
   }
 
+  get _inputNode() {
+    return /** @type {HTMLInputElement} */ (super._inputNode);
+  }
+
   constructor() {
     super();
     /** @param {string} modelValue */

packages/providence-analytics/package.json

@@ -34,7 +34,7 @@
     "@babel/traverse": "^7.5.5",
     "@babel/types": "^7.9.0",
     "@rollup/plugin-node-resolve": "^7.1.1",
-    "@typescript-eslint/typescript-estree": "^2.0.0",
+    "@typescript-eslint/typescript-estree": "^3.0.0",
     "anymatch": "^3.1.1",
     "chalk": "^4.1.0",
     "commander": "^2.20.0",
@@ -49,8 +49,7 @@
     "ora": "^3.4.0",
     "parse5": "^5.1.1",
     "read-package-tree": "5.3.1",
-    "semver": "^7.1.3",
-    "typescript": "^3.8.3"
+    "semver": "^7.1.3"
   },
   "devDependencies": {
     "mermaid": "^8.2.6",

tsconfig.json

@@ -12,7 +12,8 @@
     "alwaysStrict": true,
     "types": ["node", "mocha", "sinon"],
     "esModuleInterop": true,
-    "suppressImplicitAnyIndexErrors": true
+    "suppressImplicitAnyIndexErrors": true,
+    "skipLibCheck": true
   },
   "include": ["packages/**/*.js"],
   "exclude": [