javascript - 在对象的子键内分配一个键值

Question

我有一个对象:

let names = { field1: 'ton', field2: null }  // or field3 does not exist

我需要根据名称对象中的变量元素插入

field='field2'
relative='brotherage'
names[field][relative] =  30;  // has no effect in my code, why ?

得到这个:

 { field1: 'ton', field2: {brotherage: 30 } }

并使用此类代码向字段添加更多元素:

field='field2'
relative='cousinage'
names[field][relative] =  20;  // has no effect in my code, why ?

得到这个:

 { field1: 'ton', field2: {brotherage: 30, cousingage: 30 } }

什么是最好的方法或为什么我失败了...我尝试了很多东西但我迷路了...

Answer 1

你必须先用一个空对象初始化 names[field] :

let names = { field1: 'ton', field2: {} }

field='field2'
relative='brotherage'
names[field][relative] = 30

field='field2'
relative='cousinage'
names[field][relative] = 20

console.log(names)