angular - 如何从以下本地 json 文件访问密钥？

Question

我想访问本地 json 文件中存在的所有密钥。当我使用 Object.keys(data) 时，它返回 0。我检查了控制台中的输出，默认情况下 json 的输出映射到 0。所以请告诉我如何访问密钥。

    public ngOnInit(){
        this._logger.info("Header Mapping Component Initialized");
        this.httpClient.get("applauncher/input.json").subscribe(res=>{
            this.products=res;
            this.keys=Object.keys(this.products);
            console.log("Mapping data",this.keys);
        });


input.json



[
{
    "College1": [
        [
            "Studname1"
        ],
        [
            "Studname2"
        ]
    ],
    "College2": [
        [
            "Stud1"
        ]
    ],
}

]

标签： angular

Answer 1

你可以简单地做

const list = [{
  "College1": [
    [
      "Studname1"
    ],
    [
      "Studname2"
    ]
  ],
  "College2": [
    [
      "Stud1"
    ]
  ],
}]
const keys = list.map(item => Object.keys(item));

console.log(keys[0]);

输出 => ["College1", "College2"]