# 练习
# 对象差集
# 1、T中存在，U中不存在的对象
type D<T, U> = T extends U ? never : T; // Exclude
type Deff<T, U> = {
[k in D<keyof T, keyof U>]: T[k];
};
// 或者
type Deff<T, U> = {
[k in Exclude<keyof T, keyof U>]: T[k];
};
const a = { name: 1, age: 18, sex: 99 };
const b = { name: 2, age: 1, grade: 99 };
const c: Deff<{ name: number; age: number; sex: number }, { name: number; age: number }> = { sex: 66 };
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# 2、T中存在，U中也存在的对象
type D<T, U> = T extends U ? T : never; // Extract
type Deff<T, U> = {
[k in D<keyof T, keyof U>]: T[k];
};
// 或者
type Deff<T, U> = {
[k in Extract<keyof T, keyof U>]: T[k];
};
const a = { name: 1, age: 18, sex: 99 };
const b = { name: 2, age: 1, grade: 99 };
const c: Deff<{ name: number; age: number; sex: number }, { name: number; age: number }> = { name: 2, age: 1 };
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# 3、T中不存在，U存在；T存在，U不存在
type D<T, U> = T extends U ? never : T;
type Deff<T, U> = {
[k in D<keyof T, keyof U>]: T[k];
};
type DC<T, U> = Deff<T, U> & Deff<U, T>;
const a = { name: 1, age: 18, sex: 99 };
const b = { name: 2, age: 1, grade: 99 };
const c: DC<{ name: number; age: number; sex: number }, { name: number; age: number }> = { sex: 66 };
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