Dynamic tag in JSON - json

Question

I am generating one JSON file and I have a variable of the below type in TypeScript:
export interface Rules{
name: string,
condition: string,
}
I want to parse the 'Rule' type in JSON in the below format:
"dataRetentionRules": {
"RULE_1": {
"name": "test123",
"condition": "RetentionStartDate"
},
"RULE_2": {
"name": "test456",
"condition": "RetentionEndDate"
}
}
How can I make this rule tag dynamic? I mean how do I parse this "RULE_1", "RULE_2" tag? Since tags are supposed to be constant I believe. How can I achieve the above format?

Answer 1

You can make use of the typescript Record built-in type. Behind the scenes you are using the principles of index types and mapped types.
But all that you really need to know it this: Record<string, Rules> defines an object whose keys are strings and whose values are instances of Rules.
Your JSON object can be described by
interface HasRetentionRules {
dataRetentionRules: Record<string, Rules>
}
Note that this is asserting that any string key corresponds to a Rules object and it does not check for invalid keys, so you need to check for invalid keys yourself. Alternatively, you can use Partial<Record<string, Rules>> which states that any string key has a value which is of type Rules or undefined.
Typescript Playground Link