Function normalizeToArray

libs/echarts/echarts.simple.js:11727–11733

* If value is not array, then translate it to array. * @param {*} value * @return {Array} [value] or value

(value)

 * @return {Array} [value] or value
 */
function normalizeToArray(value) {
    return value instanceof Array
        ? value
        : value == null
        ? []
        : [value];
}

/**
 * Sync default option between normal and emphasis like `position` and `show`