feat: prepare for TS defs generation [skip ci]

[web-padawan]

Fixes #116

Generated TS definitions look like this:

vaadin-grid-pro-edit-column.d.ts

import {FlattenedNodesObserver} from '@polymer/polymer/lib/utils/flattened-nodes-observer.js';

import {get, set} from '@polymer/polymer/lib/utils/path.js';

import {GridColumnElement} from '@vaadin/vaadin-grid/src/vaadin-grid-column.js';

declare class GridProEditColumnElement extends GridColumnElement {
  path: string|null|undefined;
  editModeRenderer: GridBodyRenderer|undefined;
  editorOptions: string[];
  editorType: GridProEditorType;
  editorValuePath: string;
  ready(): void;
  _prepareBodyTemplate(): HTMLTemplateElement|null;
  _selectFirstTemplate(header?: boolean, footer?: boolean, editor?: boolean): HTMLTemplateElement|null;
  _findTemplate(header: boolean, footer: boolean, editor?: boolean): HTMLTemplateElement|null;
  _getEditorTagName(cell: HTMLElement): string;
  _getEditorComponent(cell: HTMLElement): HTMLElement|null;
  _getEditorValue(editor: HTMLElement): string|undefined;
  _startCellEdit(cell: HTMLElement, model: GridRowData): void;
  _stopCellEdit(cell: HTMLElement, model: GridRowData): void;
}

declare global {
  interface HTMLElementTagNameMap {
    "vaadin-grid-pro-edit-column": GridProEditColumnElement;
  }
}

export {GridProEditColumnElement};

import {GridBodyRenderer} from '@vaadin/vaadin-grid/@types/interfaces';

import {GridProEditorType} from '../@types/interfaces';

import {GridRowData} from '@vaadin/vaadin-grid/@types/interfaces';

vaadin-grid-pro-inline-editing-mixin.d.ts

import {microTask} from '@polymer/polymer/lib/utils/async.js';

import {Debouncer} from '@polymer/polymer/lib/utils/debounce.js';

import {PolymerElement} from '@polymer/polymer/polymer-element.js';

export {InlineEditingMixin};

declare function InlineEditingMixin<T extends new (...args: any[]) => {}>(base: T): T & InlineEditingMixinConstructor;

interface InlineEditingMixinConstructor {
  new(...args: any[]): InlineEditingMixin;
}

export {InlineEditingMixinConstructor};

interface InlineEditingMixin {
  enterNextRow: boolean|null|undefined;
  singleCellEdit: boolean|null|undefined;
  ready(): void;
  _checkImports(): void;
  _stopEdit(shouldCancel?: boolean, shouldRestoreFocus?: boolean): void;
  _switchEditCell(e: KeyboardEvent): void;
  _updateItem(row: HTMLElement, item: GridItem|null): void;
}

import {GridItem} from '@vaadin/vaadin-grid/@types/interfaces';

vaadin-grid-pro.d.ts

import {GridElement} from '@vaadin/vaadin-grid/src/vaadin-grid.js';

import {InlineEditingMixin} from './vaadin-grid-pro-inline-editing-mixin.js';

declare class GridProElement extends
  InlineEditingMixin(
  GridElement) {
  static _finalizeClass(): void;
}

declare global {
  interface HTMLElementTagNameMap {
    "vaadin-grid-pro": GridProElement;
  }
}

export {GridProElement};