打字稿中的 GUID / UUID 类型

Question

我有这个功能：

function getProduct(id: string){    
    //return some product 
}

其中 id 实际上是 GUID。 Typescript 没有 guid 类型。是否可以手动创建类型 GUID？

function getProduct(id: GUID){    
    //return some product 
}

所以如果 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx' 会是一些 'notGuidbutJustString' 那么我会看到 typescript 编译错误。

更新： 正如 David Sherret 所说：无法在编译时确保基于正则表达式或其他函数的字符串值，但可以在运行时间一个地方。

Answer 1

您可以围绕字符串创建包装器并将其传递：

class GUID {
    private str: string;

    constructor(str?: string) {
        this.str = str || GUID.getNewGUIDString();
    }

    toString() {
        return this.str;
    }

    private static getNewGUIDString() {
        // your favourite guid generation function could go here
        // ex: 
        let d = new Date().getTime();
        if (window.performance && typeof window.performance.now === "function") {
            d += performance.now(); //use high-precision timer if available
        }
        return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
            let r = (d + Math.random() * 16) % 16 | 0;
            d = Math.floor(d/16);
            return (c=='x' ? r : (r & 0x3 | 0x8)).toString(16);
        });
    }
}

function getProduct(id: GUID) {    
    alert(id); // alerts "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx"
}

const guid = new GUID("xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx");
getProduct(guid); // ok
getProduct("notGuidbutJustString"); // errors, good

const guid2 = new GUID();
console.log(guid2.toString()); // some guid string

更新

另一种方法是使用品牌：

type Guid = string & { _guidBrand: undefined };

function makeGuid(text: string): Guid {
  // todo: add some validation and normalization here
  return text as Guid;
}

const someValue = "someString";
const myGuid = makeGuid("ef3c1860-5ce6-47af-a13d-1ed72f65b641");

expectsGuid(someValue); // error, good
expectsGuid(myGuid); // ok, good

function expectsGuid(guid: Guid) {
}

Answer 2

我认为应该扩展一下 David Sherret 的回答。
像这样：

// export 
class InvalidUuidError extends Error {
    constructor(m?: string) {
        super(m || "Error: invalid UUID !");

        // Set the prototype explicitly.
        Object.setPrototypeOf(this, InvalidUuidError.prototype);
    }

}


// export 
class UUID 
{
    protected m_str: string;

    constructor(str?: string) {
        this.m_str = str || UUID.newUuid().toString();

        let reg:RegExp = new RegExp("[A-F0-9]{8}-[A-F0-9]{4}-[A-F0-9]{4}-[A-F0-9]{4}-[A-F0-9]{12}", "i")
        if(!reg.test(this.m_str))
            throw new InvalidUuidError();
    }

    toString() {
        return this.m_str;
    }

    public static newUuid(version?:number) :UUID
    {
        version = version || 4;


        // your favourite guid generation function could go here
        // ex: 
        let d = new Date().getTime();
        if (window.performance && typeof window.performance.now === "function") {
            d += performance.now(); //use high-precision timer if available
        }
        let uuid:string = ('xxxxxxxx-xxxx-' + version.toString().substr(0,1) + 'xxx-yxxx-xxxxxxxxxxxx').replace(/[xy]/g, (c) => {
            let r = (d + Math.random() * 16) % 16 | 0;
            d = Math.floor(d/16);
            return (c=='x' ? r : (r & 0x3 | 0x8)).toString(16);
        });

        return new UUID(uuid);
    }
}


function getProduct(id: UUID) {    
    alert(id); // alerts "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx"
}


const guid2 = new UUID();
console.log(guid2.toString()); // some guid string


const guid = new UUID("xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx");
getProduct(guid); // ok
getProduct("notGuidbutJustString"); // errors, good

Answer 3

我真的很喜欢@DavidSherret 的更新版本使用强类型基元的惯用方法，即通过品牌类型/标记联合类型 (+1)。

通过为品牌添加类型参数对其进行扩展，甚至可以将 ID 绑定到特定实体或对象类型（如 OP 问题中的“产品”）：

type OptionalRecord = Record<string, unknown> | undefined

type Uuid<T extends OptionalRecord = undefined> = string & { __uuidBrand: T }

type Product = {
    id: Uuid<Product>
    name: string
}

type ProductId = Product['id']

function uuid<T extends OptionalRecord = undefined>(value: string) {
    return value as Uuid<T>
}

function productId(value: string) {
    return uuid<Product>(value)
}

function funcWithProductIdArg(productId: ProductId) {
    // do something
    return productId
}

const concreteProductId = productId('123e4567-e89b-12d3-a456-426614174000')

// compiles
funcWithProductIdArg(concreteProductId)

// Argument of type 'string' is not assignable to parameter of type 'ProductId'.
//  Type 'string' is not assignable to type '{ __uuidBrand: Product; }'.(2345)
//
// @ts-expect-error Not a ProductId.
funcWithProductIdArg('123e4567-e89b-12d3-a456-426614174000')

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打字稿中的 GUID / UUID 类型

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