1. JS获取对象属性需先判空

TypeScript 3.7 Optional Chaining

参考：阮一峰《ES6入门》链判断运算符

 const data = {product:{productId:12},order:null}
 const productId  = data?.product?.productId     //12
 const orderId = data?.order?.orderId    //undefined\
 
 // optional chaining 的应用场景
 obj?.prop       // optional static property access
 obj?.[expr]     // optional dynamic property access
 func?.(...args) // optional function or method call

Loadsh

const data = {product:{productId:12},order:null}
const productId  = _.get(data,"product.productId")  //12
const orderId = _.get(data,"order.orderId")  //undefined