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
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
|
=== tests/cases/compiler/deepKeysIndexing.ts ===
// regression test from https://github.com/Microsoft/TypeScript/issues/29692
interface DeepObject {
[k1: string]: {
>k1 : string
[k2: string]: any;
>k2 : string
};
}
type keys2broken<
>keys2broken : keys2broken<O, K1>
O extends DeepObject,
K1 extends keyof O
> = O[K1] extends object ? Extract<keyof O[K1], string> : never;
type keys2working<
>keys2working : keys2working<O, K1>
O extends DeepObject,
K1 extends keyof O
> = O[K1] extends object ? keyof O[K1] : never;
type keys2workaround<O extends DeepObject, K1 extends keyof O> = Extract<
>keys2workaround : keys2workaround<O, K1>
O[K1] extends object ? keyof O[K1] : never,
string
>;
interface Foo extends DeepObject {
a: {
>a : { "1": 123; "2": string; "3": boolean; }
"1": 123;
>"1" : 123
"2": string;
>"2" : string
"3": boolean;
>"3" : boolean
};
}
class Bar<O extends DeepObject> {
>Bar : Bar<O>
broken<
>broken : <K1 extends keyof O, K2 extends keys2broken<O, K1>, V extends O[K1][K2]>(k1: K1, k2: K2, value: V) => void
K1 extends keyof O,
K2 extends keys2broken<O, K1>,
V extends O[K1][K2]
>(k1: K1, k2: K2, value: V) {}
>k1 : K1
>k2 : K2
>value : V
working<
>working : <K1 extends keyof O, K2 extends keys2working<O, K1>, V extends O[K1][K2]>(k1: K1, k2: K2, value: V) => void
K1 extends keyof O,
K2 extends keys2working<O, K1>,
V extends O[K1][K2]
>(k1: K1, k2: K2, value: V) {}
>k1 : K1
>k2 : K2
>value : V
workaround<
>workaround : <K1 extends keyof O, K2 extends Extract<O[K1] extends object ? keyof O[K1] : never, string>, V extends O[K1][K2]>(k1: K1, k2: K2, value: V) => void
K1 extends keyof O,
K2 extends keys2workaround<O, K1>,
V extends O[K1][K2]
>(k1: K1, k2: K2, value: V) {}
>k1 : K1
>k2 : K2
>value : V
}
const bar = new Bar<Foo>();
>bar : Bar<Foo>
>new Bar<Foo>() : Bar<Foo>
>Bar : typeof Bar
// all 3 of the below should error on passing `true` for `"1"`
bar.broken("a", "1", true); // was broken in the past - with 2nd argument incorrectly of type "1" | "2" | "3".
>bar.broken("a", "1", true) : void
>bar.broken : <K1 extends keyof Foo, K2 extends keys2broken<Foo, K1>, V extends Foo[K1][K2]>(k1: K1, k2: K2, value: V) => void
>bar : Bar<Foo>
>broken : <K1 extends keyof Foo, K2 extends keys2broken<Foo, K1>, V extends Foo[K1][K2]>(k1: K1, k2: K2, value: V) => void
>"a" : "a"
>"1" : "1"
>true : true
bar.working("a", "1", true); // ok - true is not allowed
>bar.working("a", "1", true) : void
>bar.working : <K1 extends keyof Foo, K2 extends keys2working<Foo, K1>, V extends Foo[K1][K2]>(k1: K1, k2: K2, value: V) => void
>bar : Bar<Foo>
>working : <K1 extends keyof Foo, K2 extends keys2working<Foo, K1>, V extends Foo[K1][K2]>(k1: K1, k2: K2, value: V) => void
>"a" : "a"
>"1" : "1"
>true : true
bar.workaround("a", "1", true); // ok - true is not allowed
>bar.workaround("a", "1", true) : void
>bar.workaround : <K1 extends keyof Foo, K2 extends Extract<Foo[K1] extends object ? keyof Foo[K1] : never, string>, V extends Foo[K1][K2]>(k1: K1, k2: K2, value: V) => void
>bar : Bar<Foo>
>workaround : <K1 extends keyof Foo, K2 extends Extract<Foo[K1] extends object ? keyof Foo[K1] : never, string>, V extends Foo[K1][K2]>(k1: K1, k2: K2, value: V) => void
>"a" : "a"
>"1" : "1"
>true : true
|
