function init(dom, theme$$1, opts) {
    if (__DEV__) {
        // Check version
        if ((version$1.replace('.', '') - 0) < (dependencies.zrender.replace('.', '') - 0)) {
            throw new Error(
                'zrender/src ' + version$1
                + ' is too old for ECharts ' + version
                + '. Current version need ZRender '
                + dependencies.zrender + '+'
            );
        }

        if (!dom) {
            throw new Error('Initialize failed: invalid dom.');
        }
    }

    var existInstance = getInstanceByDom(dom);
    if (existInstance) {
        if (__DEV__) {
            console.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))
            )
        ) {
            console.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.');
        }
    }

    var chart = new ECharts(dom, theme$$1, opts);
    chart.id = 'ec_' + idBase++;
    instances[chart.id] = chart;

    setAttribute(dom, DOM_ATTRIBUTE_KEY, chart.id);

    enableConnect(chart);

    return chart;
}
Get dimensions of specified coordinate system.
@param {string} type
@return {Array.<string|Object>}