File: flowControlTypeGuardThenSwitch.ts

package info (click to toggle)
node-typescript 3.3.3333-1
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 324,548 kB
  • sloc: makefile: 6; sh: 3
file content (35 lines) | stat: -rw-r--r-- 549 bytes parent folder | download | duplicates (5) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
 
enum Kind {
    A,
    B,
}

interface Base {
    kind: Kind;
}

interface A extends Base {
    kind: Kind.A;
    yar: any;
}

interface B extends Base {
    kind: Kind.B;
    gar: any;
}

type Both = A | B;
function isBoth(x: Base): x is Both {
    return true;
}

let foo: Base = undefined;
if (isBoth(foo)) {
    switch (foo.kind) {
        case Kind.A:
            const myA: A = foo; // Should not be an error
            break;
        case Kind.B:
            const myB: B = foo;
            break;
    }
}