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//// [literalTypeWidening.ts]
// Widening vs. non-widening literal types
function f1() {
const c1 = "hello"; // Widening type "hello"
let v1 = c1; // Type string
const c2 = c1; // Widening type "hello"
let v2 = c2; // Type string
const c3: "hello" = "hello"; // Type "hello"
let v3 = c3; // Type "hello"
const c4: "hello" = c1; // Type "hello"
let v4 = c4; // Type "hello"
}
function f2(cond: boolean) {
const c1 = cond ? "foo" : "bar"; // widening "foo" | widening "bar"
const c2: "foo" | "bar" = c1; // "foo" | "bar"
const c3 = cond ? c1 : c2; // "foo" | "bar"
const c4 = cond ? c3 : "baz"; // "foo" | "bar" | widening "baz"
const c5: "foo" | "bar" | "baz" = c4; // "foo" | "bar" | "baz"
let v1 = c1; // string
let v2 = c2; // "foo" | "bar"
let v3 = c3; // "foo" | "bar"
let v4 = c4; // string
let v5 = c5; // "foo" | "bar" | "baz"
}
function f3() {
const c1 = 123; // Widening type 123
let v1 = c1; // Type number
const c2 = c1; // Widening type 123
let v2 = c2; // Type number
const c3: 123 = 123; // Type 123
let v3 = c3; // Type 123
const c4: 123 = c1; // Type 123
let v4 = c4; // Type 123
}
function f4(cond: boolean) {
const c1 = cond ? 123 : 456; // widening 123 | widening 456
const c2: 123 | 456 = c1; // 123 | 456
const c3 = cond ? c1 : c2; // 123 | 456
const c4 = cond ? c3 : 789; // 123 | 456 | widening 789
const c5: 123 | 456 | 789 = c4; // 123 | 456 | 789
let v1 = c1; // number
let v2 = c2; // 123 | 456
let v3 = c3; // 123 | 456
let v4 = c4; // number
let v5 = c5; // 123 | 456 | 789
}
function f5() {
const c1 = "foo";
let v1 = c1;
const c2: "foo" = "foo";
let v2 = c2;
const c3 = "foo" as "foo";
let v3 = c3;
const c4 = <"foo">"foo";
let v4 = c4;
}
// Repro from #10898
type FAILURE = "FAILURE";
const FAILURE = "FAILURE";
type Result<T> = T | FAILURE;
function doWork<T>(): Result<T> {
return FAILURE;
}
function isSuccess<T>(result: Result<T>): result is T {
return !isFailure(result);
}
function isFailure<T>(result: Result<T>): result is FAILURE {
return result === FAILURE;
}
function increment(x: number): number {
return x + 1;
}
let result = doWork<number>();
if (isSuccess(result)) {
increment(result);
}
// Repro from #10898
type TestEvent = "onmouseover" | "onmouseout";
function onMouseOver(): TestEvent { return "onmouseover"; }
let x = onMouseOver();
//// [literalTypeWidening.js]
// Widening vs. non-widening literal types
function f1() {
var c1 = "hello"; // Widening type "hello"
var v1 = c1; // Type string
var c2 = c1; // Widening type "hello"
var v2 = c2; // Type string
var c3 = "hello"; // Type "hello"
var v3 = c3; // Type "hello"
var c4 = c1; // Type "hello"
var v4 = c4; // Type "hello"
}
function f2(cond) {
var c1 = cond ? "foo" : "bar"; // widening "foo" | widening "bar"
var c2 = c1; // "foo" | "bar"
var c3 = cond ? c1 : c2; // "foo" | "bar"
var c4 = cond ? c3 : "baz"; // "foo" | "bar" | widening "baz"
var c5 = c4; // "foo" | "bar" | "baz"
var v1 = c1; // string
var v2 = c2; // "foo" | "bar"
var v3 = c3; // "foo" | "bar"
var v4 = c4; // string
var v5 = c5; // "foo" | "bar" | "baz"
}
function f3() {
var c1 = 123; // Widening type 123
var v1 = c1; // Type number
var c2 = c1; // Widening type 123
var v2 = c2; // Type number
var c3 = 123; // Type 123
var v3 = c3; // Type 123
var c4 = c1; // Type 123
var v4 = c4; // Type 123
}
function f4(cond) {
var c1 = cond ? 123 : 456; // widening 123 | widening 456
var c2 = c1; // 123 | 456
var c3 = cond ? c1 : c2; // 123 | 456
var c4 = cond ? c3 : 789; // 123 | 456 | widening 789
var c5 = c4; // 123 | 456 | 789
var v1 = c1; // number
var v2 = c2; // 123 | 456
var v3 = c3; // 123 | 456
var v4 = c4; // number
var v5 = c5; // 123 | 456 | 789
}
function f5() {
var c1 = "foo";
var v1 = c1;
var c2 = "foo";
var v2 = c2;
var c3 = "foo";
var v3 = c3;
var c4 = "foo";
var v4 = c4;
}
var FAILURE = "FAILURE";
function doWork() {
return FAILURE;
}
function isSuccess(result) {
return !isFailure(result);
}
function isFailure(result) {
return result === FAILURE;
}
function increment(x) {
return x + 1;
}
var result = doWork();
if (isSuccess(result)) {
increment(result);
}
function onMouseOver() { return "onmouseover"; }
var x = onMouseOver();
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