Proper way to declare json object (typescript)

January 16, 2022

I have the following json file with data:

[{
    "sectionKey": "key1",
    "sectionName": "name",
    "content": []
  },
  {
    "sectionKey": "key2",
    "sectionName": "name",
    "content": []
  }
]

My question is: how to declare the content of the array in typescript? like "Type"[].
Please do not suggest using any[] since it removes all type checking provided by TypeScript.

>Solution :

interface CoolObject {
  sectionKey: string;
  sectionName: string;
  content: Array<any>;
}

const greatArray: CoolObject[] = [
  {
    sectionKey: 'key1',
    sectionName: 'name',
    content: [],
  },
  {
    sectionKey: 'key2',
    sectionName: 'name',
    content: [],
    foobar: 'something' // not assignable to type 'CoolObject'
  },
];

If it’s the ‘content’ poperty you’re trying to typehint you can use Array<YourType> or YourType[] too.