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
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
=== tests/cases/compiler/typeGuardNarrowsIndexedAccessOfKnownProperty6.ts ===
declare const aIndex: "key";
>aIndex : "key"
const a: { key?: { x?: number } } = {};
>a : { key?: { x?: number | undefined; } | undefined; }
>key : { x?: number | undefined; } | undefined
>x : number | undefined
>{} : {}
if (a[aIndex] && a[aIndex].x) {
>a[aIndex] && a[aIndex].x : number | undefined
>a[aIndex] : { x?: number | undefined; } | undefined
>a : { key?: { x?: number | undefined; } | undefined; }
>aIndex : "key"
>a[aIndex].x : number | undefined
>a[aIndex] : { x?: number | undefined; }
>a : { key?: { x?: number | undefined; } | undefined; }
>aIndex : "key"
>x : number | undefined
a[aIndex].x // number
>a[aIndex].x : number
>a[aIndex] : { x?: number | undefined; }
>a : { key?: { x?: number | undefined; } | undefined; }
>aIndex : "key"
>x : number
}
declare const bIndex: "key";
>bIndex : "key"
const b: { key: { x?: number } } = { key: {} };
>b : { key: { x?: number;}; }
>key : { x?: number | undefined; }
>x : number | undefined
>{ key: {} } : { key: {}; }
>key : {}
>{} : {}
if (b[bIndex].x) {
>b[bIndex].x : number | undefined
>b[bIndex] : { x?: number | undefined; }
>b : { key: { x?: number | undefined; }; }
>bIndex : "key"
>x : number | undefined
b[bIndex].x // number
>b[bIndex].x : number
>b[bIndex] : { x?: number | undefined; }
>b : { key: { x?: number | undefined; }; }
>bIndex : "key"
>x : number
}
declare const cIndex: 1;
>cIndex : 1
interface Foo {
x: number | undefined;
>x : number | undefined
}
const c: Foo[] = [];
>c : Foo[]
>[] : never[]
if (c[cIndex].x) {
>c[cIndex].x : number | undefined
>c[cIndex] : Foo
>c : Foo[]
>cIndex : 1
>x : number | undefined
c[cIndex].x // number
>c[cIndex].x : number
>c[cIndex] : Foo
>c : Foo[]
>cIndex : 1
>x : number
}
|
