isXoverlap(j) {
    let w = this.w
    let xSameForAllSeriesJArr = []

    const seriesX = w.globals.seriesX.filter((s) => typeof s[0] !== 'undefined')

    if (seriesX.length > 0) {
      for (let i = 0; i < seriesX.length - 1; i++) {
        if (
          typeof seriesX[i][j] !== 'undefined' &&
          typeof seriesX[i + 1][j] !== 'undefined'
        ) {
          if (seriesX[i][j] !== seriesX[i + 1][j]) {
            xSameForAllSeriesJArr.push('unEqual')
          }
        }
      }
    }

    if (xSameForAllSeriesJArr.length === 0) {
      return true
    }

    return false
  }
When there are multiple series, it is possible to have different x values for each series.
But it may be possible in those multiple series, that there is same x value for 2 or more
series.
@memberof Utils
@param {int}
- j = is the inner index of series -> (series[i][j])
@return {bool}