satisfies مقابل تأكيد as

ما الذي يفعله as

const value = { color: "red" } as { color: string; size: number };
// No error even though size is missing!
console.log(value.color);

يتجاوز as إجراءات الأمان

type Config = { color: string; size: number };
const broken = { color: "red" } as Config;
// broken.size is typed number but is actually undefined at runtime
console.log(broken.size); // undefined

يُجري satisfies التحقق بدلًا من ذلك

type Config = { color: string; size: number };
// const c = { color: "red" } satisfies Config; // Error: size missing
const c = { color: "red", size: 10 } satisfies Config;
console.log(c.size);

يمكن لـ as فرض أنواع خاطئة

const n = "hello" as unknown as number;
// n is typed number but is actually a string
console.log(typeof n); // "string"

لا يقدّم satisfies معلومات خاطئة عن القيم

// const x = "hello" satisfies number; // Error: string not assignable to number
const y = 42 satisfies number;
console.log(y);

يفقد as فحوص الخصائص الزائدة

type Config = { mode: string };
const withAs = { mdoe: "dark" } as Config;   // typo passes silently
// const withSat = { mdoe: "dark" } satisfies Config; // Error: mdoe
console.log(JSON.stringify(withAs));

متى يكون استخدام as مبررًا

const data: unknown = JSON.parse("{ }");
// After your own runtime validation, as can express the result.
const obj = data as Record<string, unknown>;
console.log(typeof obj);

تفضيل satisfies للإعدادات

type Palette = Record<string, string>;
const safe = { primary: "blue", accent: "gold" } satisfies Palette;
console.log(safe.primary);

يختلف as const

type Nums = readonly number[];
const xs = [1, 2, 3] as const satisfies Nums;
console.log(xs[0]);

ملخص المخاطر

type Config = { level: number };
// const risky = {} as Config; // compiles, level is undefined
const safe = { level: 1 } satisfies Config;
console.log(safe.level);

إعادة هيكلة as إلى satisfies

type Config = { url: string; retries: number };
// Before: const c = { url: "/api" } as Config;
const c = { url: "/api", retries: 3 } satisfies Config;
console.log(c.url, c.retries);

اختبار سريع: satisfies مقابل as

مراجعة: satisfies مقابل تأكيد as

type Config = { color: string; size: number };
const c = { color: "red", size: 10 } satisfies Config;
console.log(c.color, c.size);