Export `ECharts` class in TypeScript

Version

5.0

What problem does this feature solve?

The init function returns a class of type ECharts. This works fine as long as you use the chart variable right after initalization.

import {init, EChartsOption} from "echarts";
...
export class BaseChart {
  initChart() {
    const chart = init(nativeElement);
    // do something else with the chart.
  }
}

But all typings get lost, when you want to pass the chart around (e.g. for updating data later on)

import {init, EChartsOption} from "echarts";
...
export class BaseChart {
  const chart: ECharts; // <--- This does not work. You can it make `any`, but then all typings are lost;
  initChart() {
    this.chart = init(nativeElement);
    // do something else with the chart.
  }
}

The TypeScript definitions do not export the ECharts class

import {ECharts} from "echarts" // <---- This is not possible

Edit Using EChartsType which is extending ECharts does not work too.

import {init, EChartsOption} from "echarts";
import {EChartsType} from "echarts/lib/echarts";
...
export class BaseChart {
  initChart() {
    const chart: EChartsType = init(nativeElement);
    // This doesn't work too
    // TS2322: Type 'ECharts' is not assignable to type 'EChartsType'.
    // Types have separate declarations of a private property '_zr'.
  }
}

What does the proposed API look like?

Extend the exports in TypeScript. Something like this:

export { ECharts, EChartsFullOption as EChartsOption, connect, disConnect, dispose, getInstanceByDom, getInstanceById, getMap, init, registerLocale, registerMap, registerTheme };

[hesamat]

Further to your comment, we are relying on the other types like BarSeriesOption, ChartDataset, etc. This change in v5 will result in losing all of the typings in our code base. Also, as a result of not exporting them none of the fields in the EchartsOptions have any types. Please consider exporting them all

[emeryao]

@ilueckel Hi, we will plan to export more types

before that, you can use

type EChartsInstance = ReturnType<init>;

as a workaround.

In my case the workaround above does not work but the codes below worked around

import * as echarts from 'echarts';
type ECharts = ReturnType<typeof echarts.init>;
let chart = echarts.init(someElement);

echarts@v5.0.0 TypeScript@v4.0.5