Function init

src/core/echarts.ts:2926–2974

(
    dom?: HTMLElement | null,
    theme?: string | object | null,
    opts?: EChartsInitOpts
)

 * @param opts.useDirtyRect Enable dirty rectangle rendering or not.
 */
export function init(
    dom?: HTMLElement | null,
    theme?: string | object | null,
    opts?: EChartsInitOpts
): EChartsType {
    const isClient = !(opts && opts.ssr);
    if (isClient) {
        if (__DEV__) {
            if (!dom) {
                throw new Error('Initialize failed: invalid dom.');
            }
        }

        const existInstance = getInstanceByDom(dom);
        if (existInstance) {
            if (__DEV__) {
                warn('There is a chart instance already initialized on the dom.');
            }
            return existInstance;
        }

        if (__DEV__) {
            if (isDom(dom)
                && dom.nodeName.toUpperCase() !== 'CANVAS'
                && (
                    (!dom.clientWidth && (!opts || opts.width == null))
                    || (!dom.clientHeight && (!opts || opts.height == null))
                )
            ) {
                warn('Can\'t get DOM width or height. Please check '
                + 'dom.clientWidth and dom.clientHeight. They should not be 0.'
                + 'For example, you may need to call this in the callback '
                + 'of window.onload.');
            }
        }
    }

    const chart = new ECharts(dom, theme, opts);
    chart.id = 'ec_' + idBase++;
    instances[chart.id] = chart;

    isClient && modelUtil.setAttribute(dom, DOM_ATTRIBUTE_KEY, chart.id);

    enableConnect(chart);

    lifecycle.trigger('afterinit', chart);

    return chart;
}

/**
 * @usage