Function eqNaN

libs/echarts/echarts-en.simple.js:734–737

* Whether is exactly NaN. Notice isNaN('a') returns true. * @param {*} value * @return {boolean}

(value)

 * @return {boolean}
 */
function eqNaN(value) {
    /* eslint-disable-next-line no-self-compare */
    return value !== value;
}

/**
 * If value1 is not null, then return value1, otherwise judget rest of values.