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//// [intrinsicTypes.ts]
type TU1 = Uppercase<'hello'>; // "HELLO"
type TU2 = Uppercase<'foo' | 'bar'>; // "FOO" | "BAR"
type TU3 = Uppercase<string>; // Uppercase<string>
type TU4 = Uppercase<any>; // Uppercase<`${any}`>
type TU5 = Uppercase<never>; // never
type TU6 = Uppercase<42>; // Error
type TL1 = Lowercase<'HELLO'>; // "hello"
type TL2 = Lowercase<'FOO' | 'BAR'>; // "foo" | "bar"
type TL3 = Lowercase<string>; // Lowercase<string>
type TL4 = Lowercase<any>; // Lowercase<`${any}`>
type TL5 = Lowercase<never>; // never
type TL6 = Lowercase<42>; // Error
type TC1 = Capitalize<'hello'>; // "Hello"
type TC2 = Capitalize<'foo' | 'bar'>; // "Foo" | "Bar"
type TC3 = Capitalize<string>; // Capitalize<string>
type TC4 = Capitalize<any>; // Capitalize<`${any}`>
type TC5 = Capitalize<never>; // never
type TC6 = Capitalize<42>; // Error
type TN1 = Uncapitalize<'Hello'>; // "hello"
type TN2 = Uncapitalize<'Foo' | 'Bar'>; // "foo" | "bar"
type TN3 = Uncapitalize<string>; // Uncapitalize<string>
type TN4 = Uncapitalize<any>; // Uncapitalize<`${any}`>
type TN5 = Uncapitalize<never>; // never
type TN6 = Uncapitalize<42>; // Error
type TX1<S extends string> = Uppercase<`aB${S}`>;
type TX2 = TX1<'xYz'>; // "ABXYZ"
type TX3<S extends string> = Lowercase<`aB${S}`>;
type TX4 = TX3<'xYz'>; // "abxyz"
type TX5 = `${Uppercase<'abc'>}${Lowercase<'XYZ'>}`; // "ABCxyz"
type MyUppercase<S extends string> = intrinsic; // Error
function foo1<T extends string, U extends T>(s: string, x: Uppercase<T>, y: Uppercase<U>) {
s = x;
s = y;
x = s; // Error
x = y;
y = s; // Error
y = x; // Error
}
function foo2<T extends 'foo' | 'bar'>(x: Uppercase<T>) {
let s: 'FOO' | 'BAR' = x;
}
declare function foo3<T extends string>(x: Uppercase<T>): T;
function foo4<U extends string>(x: Uppercase<U>) {
return foo3(x);
}
//// [intrinsicTypes.js]
"use strict";
function foo1(s, x, y) {
s = x;
s = y;
x = s; // Error
x = y;
y = s; // Error
y = x; // Error
}
function foo2(x) {
var s = x;
}
function foo4(x) {
return foo3(x);
}
//// [intrinsicTypes.d.ts]
type TU1 = Uppercase<'hello'>;
type TU2 = Uppercase<'foo' | 'bar'>;
type TU3 = Uppercase<string>;
type TU4 = Uppercase<any>;
type TU5 = Uppercase<never>;
type TU6 = Uppercase<42>;
type TL1 = Lowercase<'HELLO'>;
type TL2 = Lowercase<'FOO' | 'BAR'>;
type TL3 = Lowercase<string>;
type TL4 = Lowercase<any>;
type TL5 = Lowercase<never>;
type TL6 = Lowercase<42>;
type TC1 = Capitalize<'hello'>;
type TC2 = Capitalize<'foo' | 'bar'>;
type TC3 = Capitalize<string>;
type TC4 = Capitalize<any>;
type TC5 = Capitalize<never>;
type TC6 = Capitalize<42>;
type TN1 = Uncapitalize<'Hello'>;
type TN2 = Uncapitalize<'Foo' | 'Bar'>;
type TN3 = Uncapitalize<string>;
type TN4 = Uncapitalize<any>;
type TN5 = Uncapitalize<never>;
type TN6 = Uncapitalize<42>;
type TX1<S extends string> = Uppercase<`aB${S}`>;
type TX2 = TX1<'xYz'>;
type TX3<S extends string> = Lowercase<`aB${S}`>;
type TX4 = TX3<'xYz'>;
type TX5 = `${Uppercase<'abc'>}${Lowercase<'XYZ'>}`;
type MyUppercase<S extends string> = intrinsic;
declare function foo1<T extends string, U extends T>(s: string, x: Uppercase<T>, y: Uppercase<U>): void;
declare function foo2<T extends 'foo' | 'bar'>(x: Uppercase<T>): void;
declare function foo3<T extends string>(x: Uppercase<T>): T;
declare function foo4<U extends string>(x: Uppercase<U>): U;
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