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typeGuardIntersectionTypes.types
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typeGuardIntersectionTypes.types
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=== tests/cases/conformance/expressions/typeGuards/typeGuardIntersectionTypes.ts ===
interface X {
x: string;
>x : string
}
interface Y {
y: string;
>y : string
}
interface Z {
z: string;
>z : string
}
declare function isX(obj: any): obj is X;
>isX : (obj: any) => obj is X
>obj : any
declare function isY(obj: any): obj is Y;
>isY : (obj: any) => obj is Y
>obj : any
declare function isZ(obj: any): obj is Z;
>isZ : (obj: any) => obj is Z
>obj : any
function f1(obj: Object) {
>f1 : (obj: Object) => void
>obj : Object
if (isX(obj) || isY(obj) || isZ(obj)) {
>isX(obj) || isY(obj) || isZ(obj) : boolean
>isX(obj) || isY(obj) : boolean
>isX(obj) : boolean
>isX : (obj: any) => obj is X
>obj : Object
>isY(obj) : boolean
>isY : (obj: any) => obj is Y
>obj : Object
>isZ(obj) : boolean
>isZ : (obj: any) => obj is Z
>obj : Object
obj;
>obj : X | Y | Z
}
if (isX(obj) && isY(obj) && isZ(obj)) {
>isX(obj) && isY(obj) && isZ(obj) : boolean
>isX(obj) && isY(obj) : boolean
>isX(obj) : boolean
>isX : (obj: any) => obj is X
>obj : Object
>isY(obj) : boolean
>isY : (obj: any) => obj is Y
>obj : X
>isZ(obj) : boolean
>isZ : (obj: any) => obj is Z
>obj : X & Y
obj;
>obj : X & Y & Z
}
}
// Repro from #8911
// two interfaces
interface A {
a: string;
>a : string
}
interface B {
b: string;
>b : string
}
// a type guard for B
function isB(toTest: any): toTest is B {
>isB : (toTest: any) => toTest is B
>toTest : any
return toTest && toTest.b;
>toTest && toTest.b : any
>toTest : any
>toTest.b : any
>toTest : any
>b : any
}
// a function that turns an A into an A & B
function union(a: A): A & B | null {
>union : (a: A) => (A & B) | null
>a : A
>null : null
if (isB(a)) {
>isB(a) : boolean
>isB : (toTest: any) => toTest is B
>a : A
return a;
>a : A & B
} else {
return null;
>null : null
}
}
// Repro from #9016
declare function log(s: string): void;
>log : (s: string) => void
>s : string
// Supported beast features
interface Beast { wings?: boolean; legs?: number }
>wings : boolean | undefined
>legs : number | undefined
interface Legged { legs: number; }
>legs : number
interface Winged { wings: boolean; }
>wings : boolean
// Beast feature detection via user-defined type guards
function hasLegs(x: Beast): x is Legged { return x && typeof x.legs === 'number'; }
>hasLegs : (x: Beast) => x is Legged
>x : Beast
>x && typeof x.legs === 'number' : boolean
>x : Beast
>typeof x.legs === 'number' : boolean
>typeof x.legs : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>x.legs : number | undefined
>x : Beast
>legs : number | undefined
>'number' : "number"
function hasWings(x: Beast): x is Winged { return x && !!x.wings; }
>hasWings : (x: Beast) => x is Winged
>x : Beast
>x && !!x.wings : boolean
>x : Beast
>!!x.wings : boolean
>!x.wings : boolean
>x.wings : boolean | undefined
>x : Beast
>wings : boolean | undefined
// Function to identify a given beast by detecting its features
function identifyBeast(beast: Beast) {
>identifyBeast : (beast: Beast) => void
>beast : Beast
// All beasts with legs
if (hasLegs(beast)) {
>hasLegs(beast) : boolean
>hasLegs : (x: Beast) => x is Legged
>beast : Beast
// All winged beasts with legs
if (hasWings(beast)) {
>hasWings(beast) : boolean
>hasWings : (x: Beast) => x is Winged
>beast : Legged
if (beast.legs === 4) {
>beast.legs === 4 : boolean
>beast.legs : number
>beast : Legged & Winged
>legs : number
>4 : 4
log(`pegasus - 4 legs, wings`);
>log(`pegasus - 4 legs, wings`) : void
>log : (s: string) => void
>`pegasus - 4 legs, wings` : "pegasus - 4 legs, wings"
}
else if (beast.legs === 2) {
>beast.legs === 2 : boolean
>beast.legs : number
>beast : Legged & Winged
>legs : number
>2 : 2
log(`bird - 2 legs, wings`);
>log(`bird - 2 legs, wings`) : void
>log : (s: string) => void
>`bird - 2 legs, wings` : "bird - 2 legs, wings"
}
else {
log(`unknown - ${beast.legs} legs, wings`);
>log(`unknown - ${beast.legs} legs, wings`) : void
>log : (s: string) => void
>`unknown - ${beast.legs} legs, wings` : `unknown - ${number} legs, wings`
>beast.legs : number
>beast : Legged & Winged
>legs : number
}
}
// All non-winged beasts with legs
else {
log(`manbearpig - ${beast.legs} legs, no wings`);
>log(`manbearpig - ${beast.legs} legs, no wings`) : void
>log : (s: string) => void
>`manbearpig - ${beast.legs} legs, no wings` : `manbearpig - ${number} legs, no wings`
>beast.legs : number
>beast : Legged
>legs : number
}
}
// All beasts without legs
else {
if (hasWings(beast)) {
>hasWings(beast) : boolean
>hasWings : (x: Beast) => x is Winged
>beast : Beast
log(`quetzalcoatl - no legs, wings`)
>log(`quetzalcoatl - no legs, wings`) : void
>log : (s: string) => void
>`quetzalcoatl - no legs, wings` : "quetzalcoatl - no legs, wings"
}
else {
log(`snake - no legs, no wings`)
>log(`snake - no legs, no wings`) : void
>log : (s: string) => void
>`snake - no legs, no wings` : "snake - no legs, no wings"
}
}
}
function beastFoo(beast: Object) {
>beastFoo : (beast: Object) => void
>beast : Object
if (hasWings(beast) && hasLegs(beast)) {
>hasWings(beast) && hasLegs(beast) : boolean
>hasWings(beast) : boolean
>hasWings : (x: Beast) => x is Winged
>beast : Object
>hasLegs(beast) : boolean
>hasLegs : (x: Beast) => x is Legged
>beast : Winged
beast; // Winged & Legged
>beast : Winged & Legged
}
else {
beast;
>beast : Object
}
if (hasLegs(beast) && hasWings(beast)) {
>hasLegs(beast) && hasWings(beast) : boolean
>hasLegs(beast) : boolean
>hasLegs : (x: Beast) => x is Legged
>beast : Object
>hasWings(beast) : boolean
>hasWings : (x: Beast) => x is Winged
>beast : Legged
beast; // Legged & Winged
>beast : Legged & Winged
}
}