Typescript type for Tooltip custom positioner

[elinake]

Documentation Is:

• Missing or needed

Please Explain in Detail...

The documents suggest using tooltip custom positioner like this:

const tooltipPlugin = Chart.registry.getPlugin('tooltip');
tooltipPlugin.positioners.myCustomPositioner = function(elements, eventPosition) {
    /** @type {Tooltip} */
    var tooltip = this;

getRegistry returns the tooltip as Plugin,

The element that can be used for customized positioning like above, is

export const Tooltip: Plugin & {
  readonly positioners: {
    [key: string]: (items: readonly ActiveElement[], eventPosition: { x: number; y: number }) => { x: number; y: number } | false;
  };

  getActiveElements(): ActiveElement[];
  setActiveElements(active: ActiveDataPoint[], eventPosition: { x: number, y: number }): void;
};

Typescript 4.3.5 cannot cast the return object of getPlugin into an object with those functions. And if I mark the return object as type Plugin, typescript gives an error for not having those functions.

Your Proposal for Changes

Add interface Tooltip instead of const Tooltip

Example