earthlyBranchIndexToPalaceIndex function

int earthlyBranchIndexToPalaceIndex(
  1. EarthlyBranchName earthlyBranchName
)

因为宫位是从寅宫开始的排列的，所以需要将目标地支的序号减去寅的序号才能得到宫位的序号

@param {EarthlyBranchName} earthlyBranch 地支 @returns {number} 该地支对应的宫位索引序号

Implementation

int earthlyBranchIndexToPalaceIndex(EarthlyBranchName earthlyBranchName) {
  final earthlyBranch = earthlyBranchName.key;
  final yin = EarthlyBranchName.yinEarthly.key;
  return fixIndex(
      earthlyBranches.indexOf(earthlyBranch) - earthlyBranches.indexOf(yin));
}