2 replies

Derive Type from Parameter of function attach to object (possibly recursive idk)

Hey Guys, so to explain what I'm doing, I'm basically defining a data structure to plug into a function of mine.

The data structure is a key value and a class object that is defined on the fly. Like this

const AccountValidation: ValidationShape = {
    username: Validation.new('').length(5),
    password: Validation.new('').length(5)
}

const AccountValidation: ValidationShape = {
    username: Validation.new('').length(5),
    password: Validation.new('').length(5)
}

The

Validation.new()

Validation.new()

function is used to define the default value for each field and instantiate an object to build my validation strategy.

type ValidationShape = {
    [key: string ]: Validation<unknown>
}

type ValidationShape = {
    [key: string ]: Validation<unknown>
}

This is the ValidationShape type and here is the Validation object class

export class Validation<T> {
    default: T;
    ValidationQueue: ValidationMethod[] = [];

    constructor(val: T) {
        this.default = val;
    }

    length(min: number, max?: number) {
        this.ValidationQueue.push({
            method: 'length',
            min,
            max

        })
        return this;
    }

    getDefaultValue(): T {
        return this.default;
    }

    getValidationQueue(): ValidationMethod[] {
        return this.ValidationQueue;
    }

    static new<T>(val: T) {
        return new Validation(val);
    }

export class Validation<T> {
    default: T;
    ValidationQueue: ValidationMethod[] = [];

    constructor(val: T) {
        this.default = val;
    }

    length(min: number, max?: number) {
        this.ValidationQueue.push({
            method: 'length',
            min,
            max

        })
        return this;
    }

    getDefaultValue(): T {
        return this.default;
    }

    getValidationQueue(): ValidationMethod[] {
        return this.ValidationQueue;
    }

    static new<T>(val: T) {
        return new Validation(val);
    }

So this is the object attached to each invidual key fpr my

ValidationShape

ValidationShape

object. Now, I would like to take this shape, iterate over it and get the default value and its type and then take those values to create a new shape that is the

key: ReturnType<GetDefaultValue>

key: ReturnType<GetDefaultValue>

type Reshape = {
    [Property in keyof ValidationShape]: ReturnType<Property['getDefaultValue']>
}


const T: Reshape = {
    username: "usernme",
    password: "passwrd",
}

type Reshape = {
    [Property in keyof ValidationShape]: ReturnType<Property['getDefaultValue']>
}


const T: Reshape = {
    username: "usernme",
    password: "passwrd",
}

Notice the reshape version is now just strings, since each

new

new

call was called with an empty string.

TTC

Theo's Typesafe Cult•3y ago•

2 replies

MagerX

Derive Type from Parameter of function attach to object (possibly recursive idk)

const AccountValidation: ValidationShape = {
    username: Validation.new('').length(5),
    password: Validation.new('').length(5)
}

const AccountValidation: ValidationShape = {
    username: Validation.new('').length(5),
    password: Validation.new('').length(5)
}

The

Validation.new()

Validation.new()

function is used to define the default value for each field and instantiate an object to build my validation strategy.

type ValidationShape = {
    [key: string ]: Validation<unknown>
}

type ValidationShape = {
    [key: string ]: Validation<unknown>
}

This is the ValidationShape type and here is the Validation object class

export class Validation<T> {
    default: T;
    ValidationQueue: ValidationMethod[] = [];

    constructor(val: T) {
        this.default = val;
    }

    length(min: number, max?: number) {
        this.ValidationQueue.push({
            method: 'length',
            min,
            max

        })
        return this;
    }

    getDefaultValue(): T {
        return this.default;
    }

    getValidationQueue(): ValidationMethod[] {
        return this.ValidationQueue;
    }

    static new<T>(val: T) {
        return new Validation(val);
    }

export class Validation<T> {
    default: T;
    ValidationQueue: ValidationMethod[] = [];

    constructor(val: T) {
        this.default = val;
    }

    length(min: number, max?: number) {
        this.ValidationQueue.push({
            method: 'length',
            min,
            max

        })
        return this;
    }

    getDefaultValue(): T {
        return this.default;
    }

    getValidationQueue(): ValidationMethod[] {
        return this.ValidationQueue;
    }

    static new<T>(val: T) {
        return new Validation(val);
    }

So this is the object attached to each invidual key fpr my

ValidationShape

ValidationShape

object. Now, I would like to take this shape, iterate over it and get the default value and its type and then take those values to create a new shape that is the

key: ReturnType<GetDefaultValue>

key: ReturnType<GetDefaultValue>

type Reshape = {
    [Property in keyof ValidationShape]: ReturnType<Property['getDefaultValue']>
}


const T: Reshape = {
    username: "usernme",
    password: "passwrd",
}

type Reshape = {
    [Property in keyof ValidationShape]: ReturnType<Property['getDefaultValue']>
}


const T: Reshape = {
    username: "usernme",
    password: "passwrd",
}

Notice the reshape version is now just strings, since each

new

new

call was called with an empty string.

Derive Type from Parameter of function attach to object (possibly recursive idk)

Derive Type from Parameter of function attach to object (possibly recursive idk)

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