Javascript-使用变量作为对象键来获取对象值

Question

在下面的代码中，我想循环检索person1和person4（数组中的第一个人）。明确标识属性时，此方法有效。但是，当使用变量“ myField”表示属性时，它返回未定义的...获取值的语法是什么？

JSFiddle：https://jsfiddle.net/8vr06Ltk/3/

    var companies = [
      { 
        "description":"company1", 
        "people": [{"name":"person1"},{"name":"person2"},{"name":"person3"}],
        "date":"2020-01-01"
      },
      { 
        "description":"company2", 
        "people": [{"name":"person4"},{"name":"person5"},{"name":"person6"}],
        "date":"2020-01-01"
      } 
    ]


var myField = "people[0].name";

for (var key in companies) {
  console.log(companies[key].people[0].name); /* correct: returns person1 and person4 */
  console.log(companies[key].myField); /* incorrect: undefined */
  console.log(companies[key][myField]); /* incorrect: undefined */
}