أنواع قيم JSON

ما قيمة JSON؟

type Json =
  | string
  | number
  | boolean
  | null
  | Json[]
  | { [k: string]: Json };
// arrays and objects nest Json again.

نوع JSON التكراري

type Json =
  | string | number | boolean | null
  | Json[]
  | { [k: string]: Json };
const x: Json = { name: "Ada", tags: ["a", "b"], active: true };
console.log(x);

قيم JSON البدائية

type Json = string | number | boolean | null | Json[] | { [k: string]: Json };
const a: Json = "hello";
const b: Json = 42;
const c: Json = true;
const d: Json = null;
console.log(a, b, c, d);

مصفوفات JSON

type Json = string | number | boolean | null | Json[] | { [k: string]: Json };
const arr: Json = [1, "two", true, null, [3, 4]];
console.log(Array.isArray(arr));

كائنات JSON

type Json = string | number | boolean | null | Json[] | { [k: string]: Json };
const obj: Json = {
  user: { name: "Ada", age: 36 },
  scores: [10, 20, 30]
};
console.log(obj);

JSON متداخل بعمق

type Json = string | number | boolean | null | Json[] | { [k: string]: Json };
const deep: Json = {
  a: { b: { c: [1, { d: true }] } }
};
console.log(deep);

ما الذي يستبعده JSON

type Json = string | number | boolean | null | Json[] | { [k: string]: Json };
// const bad: Json = undefined; // Error
// const fn: Json = () => 1;   // Error
const good: Json = { ok: true };
console.log(good);

التحقق من أشكال JSON أثناء التشغيل

type Json = string | number | boolean | null | Json[] | { [k: string]: Json };
function isJson(v: unknown): v is Json {
  if (v === null) return true;
  const t = typeof v;
  if (t === "string" || t === "number" || t === "boolean") return true;
  if (Array.isArray(v)) return v.every(isJson);
  if (t === "object") return Object.values(v as object).every(isJson);
  return false;
}
console.log(isJson({ a: [1, 2], b: "x" }));

التحليل إلى نوع Json

type Json = string | number | boolean | null | Json[] | { [k: string]: Json };
const raw = "{ \"id\": 1, \"tags\": [\"a\"] }";
const parsed = JSON.parse(raw) as Json;
console.log(parsed);

اجتياز قيمة Json

type Json = string | number | boolean | null | Json[] | { [k: string]: Json };
function countLeaves(v: Json): number {
  if (Array.isArray(v)) return v.reduce((a, x) => a + countLeaves(x), 0);
  if (v !== null && typeof v === "object") return Object.values(v).reduce((a, x) => a + countLeaves(x), 0);
  return 1;
}
console.log(countLeaves({ a: [1, 2], b: "x" }));

لماذا يُعد نوع Json مفيدًا

type Json = string | number | boolean | null | Json[] | { [k: string]: Json };
function send(payload: Json): string {
  return JSON.stringify(payload);
}
console.log(send({ ok: true, items: [1, 2, 3] }));

تحقق سريع: أنواع قيم JSON

مراجعة: أنواع قيم JSON

type Json = string | number | boolean | null | Json[] | { [k: string]: Json };
const data: Json = { id: 1, tags: ["a", "b"] };
console.log(JSON.stringify(data));