1.for循环与forEach，比较简单的操作就不贴代码了，唯一不同的在于for循环内部相应break等中断操作，forEach不支持，
2.for...of，基于es6的新方法，完美支持break等中断循环操作，
for (let item of CityDataJson) {
if (nameId == item.id) {
for (let cityList of item.city) {
if (cityId == cityList.id) {
for (let areaList of cityList.area) {
if (areaId == areaList.id) {
this.setState({
provinceId: CityDataJson[preventIndex].id,
provinceDesc: CityDataJson[preventIndex].name,
cityId: cityList[cityIndex].id,
cityDesc: cityList[cityIndex].name,
areaId: areaList[areaIndex].id,
areaDesc: areaList[areaIndex].name
});
break;
}
}
break;
}
}
break;
}
}
3.基于lodash的findIndex方法，快速找到对应数据下标，代码如下；
let preventIndex = findIndex(CityDataJson, ['id', nameId]),
cityList = CityDataJson[preventIndex].city,
cityIndex = findIndex(cityList, ['id', cityId]),
areaList = cityList[cityIndex].area,
areaIndex = findIndex(areaList, ['id', areaId]);
console.log(cityIndex, cityId);
this.setState({
provinceId: CityDataJson[preventIndex].id,
provinceDesc: CityDataJson[preventIndex].name,
cityId: cityList[cityIndex].id,
cityDesc: cityList[cityIndex].name,
areaId: areaList[areaIndex].id,
areaDesc: areaList[areaIndex].name
});