Type guard and type conversion in typescript

explicit.ts

// https://www.typescriptlang.org/play?#code/C4TwDgpgBAglC8UDeBYAUFTUwCcD2YAjAFxQDOwOAlgHYDm6W2+YATKRdfY1rgQMwdKtBmgC+6dKEhQAQgigB5ALZVgAHhgAaKAHI+bXQD5JaadADCClWs079LfsdPmoADXUAVKBAAewCBoAEzJYKAAfOQioCyMFbz8A4NC4AH4w0gT-QJCo9PlSCwBuUwBjPBoKKCoyC1IPWIUkKB5MAxIoACIQPE6tVuYCdi6AdwgyAAs+9Ak0dHLK4GqyWXr1WTjEZoH20m7e-oxeRz2yAEMAGwBXYGnxMoqqmpg1mE3kFqO2lg79u6YDMNOmNJv9jgJTpcbncxEA

type A = {
    prop1: string
    prop2: string
    prop3: string
}

type B = Omit<A, 'prop2'>

type C = Omit<A, 'prop3'>

type X<T extends A | B | C> = T extends A ? A : T extends B ? B : C;

const isC: X<C> = { 
    prop1: "yo",
    prop2: "wesh",
}
  
const isB: X<B> = { 
    prop1: "yo",
    prop3: "salut",
}

const isA: X<A> = { 
    prop1: "yo",
    prop2: "wesh",
    prop3: "salut",
}

generic.ts

// https://www.typescriptlang.org/play?ssl=19&ssc=50&pln=1&pc=1#code/C4TwDgpgBAglC8UDeAoK6pgE4HswEYAuKAZ2CwEsA7AczQ2zwCZizLb71GwBmV86nQC+KFKEhQAQgigB5ALYVgAHhgAaKAHJuTTQD5R46AGEZCpao3bcvfaIgAPMDizAoRqACUIJAK4AbN0Q4AB8pKDDjeycXNw8AcQgqABVwCGVkqEdgJIATEi8fAOA9GWTRAGMcKjJYKGJElLTVUsRkbiIoACIQHC6NHWIu4D6Bmz5uqq6RFCqat2kGpNTIZUlW9CQOod7+zHGhqZm52tMlptXjDa2bTp7R-eYhkemgA
// Similar to explicit

type A = {
    prop1: string
    prop2: string
    prop3: string
}

type B = Omit<A, 'prop2'>

type C = Omit<A, 'prop3'>

export type Result = A | B | C

export type GenType<T extends Result> = T

const A : GenType<A> =  {prop1: "yo", prop2: "to", prop3: "co"}

const B : GenType<B> =  {prop1: "yo", prop3: "co"}

const C : GenType<C> = {prop1: "yo", prop2: "to"}

implicit.ts

// https://www.typescriptlang.org/play?#code/C4TwDgpgBAglC8UDeBYAUFTUwCcD2YAjAFxQDOwOAlgHYDm6W2+YATKRdfY1rgQMwdKtBmgC+6dKEhQAQgigB5ALZVgAHhgAaKAHI+bXQD5JaadADCClWs079LfsdPmoADXUAVIws9QIAB7AEDQAJmSwUAD8kaR+gcFhEfIx8qQWANymAMZ4NBRQ2TgQAIbBbgpe-kEh4VAACiU4wFQlADaaRkYAFABucQCUpB7eCD69UCURI0ZZaOi5+cBQVGRWiEWl5d1IUDyYBiRQAEQgeMda+8wE7CcA7hBkABYX6GIDcwt5BavyG8VlCBuHZ7DC8FhHU7nS5gg6OUjHMjtACuwFe4g+oK+SxWZDg-y2QJBV0OCLO6KYBluxwezwp4IECKRbVR6PeGVBQA

type A = {
    prop1: string
    prop2: string
    prop3: string
}

type B = Omit<A, 'prop2'>

type C = Omit<A, 'prop3'>

type X<T> = T extends A ? A : T extends B ? B : C;

const createX = <T extends Partial<A>>(v: T): X<T> => v as X<T>;

const isC = createX({ 
    prop1: "yo",
    prop2: "wesh",
});

const isB = createX({ 
    prop1: "yo",
    prop3: "salut",
}); 

const isA = createX({ 
    prop1: "yo",
    prop2: "wesh",
    prop3: "salut",
}); 

typeguard.ts

// https://www.typescriptlang.org/play?#code/C4TwDgpgBAglC8UDeBYAUFTUwCcD2YAjAFxQDOwOAlgHYDm6W2+YATKRdfY1rgQMwdKtBmgC+6dKEhQAQgigB5ALZVgAHhgAaKAHI+bXQD5JaadADCClWs079LfsdMBjPDQpQqZOIgAUeABGAFakcAA+UFaRsgCUpEHBXmSwCEZ6Bk5eNFCJUABk+RksrLrZuSEA3OhuHsDJ8v6JYVCR0XLxFUnecmnFBKXlidVotZ7eVk0hLW2tHQkhyVF9DgJltF0jNe6ewBCeTTO9bbF9qBhY3jABp4VQY3gANhAAdI94dAEvBqyxI0zeWQ3ApFB7PN4fL6ZP48TATYF3MGvd6fPDfFiEGHidBAA

type A = {
    prop1: string
    prop2: string
    prop3: string
}

type B = Omit<A, 'prop2'>

type C = Omit<A, 'prop3'>

const isA = (obj: A | C | B): obj is A => 'prop3' in obj && 'prop2' in obj;
const isB = (obj: A | C | B): obj is B => 'prop2' in obj;
const isC = (obj: A | C | B): obj is C => 'prop3' in obj;

const test = (o: A | B | C) => {
    isA(o) && console.log(o.prop2);
    isB(o) && console.log(o.prop3);
    isC(o) && console.log(o.prop1);
}