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Stronger type for `value` in `JSON.stringify(value: any)`

The official TypeScript lib type definition for the value argument to JSON.stringify(value) is any.

Is there a stricter type for value such that serializing and deserializing it would result the same value? In other words, such that the following were true:

deepEqual(value, JSON.parse(JSON.stringify(value)))

For example, if value were a Date object, the above statement would be false.

The answer I’m looking for is

type SerializableValue = ...
Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    Adding to Dimava's answer and this GitHub issue, type JSONValue is the closest it gets:

    type JSONValue = string | number | boolean | null | JSONObject | JSONArray;

// Helpers
type JSONObject = { [member: string]: JSONValue };
interface JSONArray extends Array<JSONValue> {}

    But, there are still some limitations:

    import { strict as assert } from 'node:assert';

assert.deepEqual(NaN, JSON.parse(JSON.stringify(NaN))) // => false
assert.deepEqual(Infinity, JSON.parse(JSON.stringify(Infinity))) // => false

  2. 0 
    type JSONSerializeable = 
| boolean
| number
| string
| null
| JSONSerializeable[]
| Record<string, JSONSerializeable>

    Technically there are more things JSON can serialize, but the above is what it can deseriaize

    You may use

    export { }
declare global {
  interface JSON {
    parse(text: string): JSONSerializeable
  }
}

let x = JSON.parse('{"foo":"bar"}')
//  ^?
// let x: JSONSerializeable

    in a my-global-types.d.ts in your project to declare it globally

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