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ViewsWhy the second argument of function become never
want to create simple generic interface for function, that accepts interface of object and first argument is key of object and second is key2 of object by object[key].
Here my solution
type Test<T extends Object, K extends keyof T = keyof T, V extends keyof T[K] = keyof T[K]> = (key: K, key2: V) => void
Object
const convertFunctionsMap = {
ms: {
h: millisecondsToHours,
s: millisecondsToSeconds,
m: millisecondsToMinutes
},
s: {
h: secondsToHours,
ms: secondsToMilliseconds,
m: secondsToMinutes
},
m: {
ms: minutesToMilliseconds,
s: minutesToSeconds,
h: minutesToHours
},
h: {
ms: hoursToMilliseconds,
s: hoursToSeconds,
m: hoursToMinutes
}
}
But I got
CodeSandbox: https://codesandbox.io/s/empty-leaf-cuz51r?file=/src/index.ts
·
Santiago Gelvez
1 answers
Answer question0
i don't how to explain, but i know it works
interface Test<T> {
<K1 extends keyof T, K2 extends keyof T[K1]>(key: K1, key2: K2): void;
}
const convertFunctionsMap = {
ms: {
h: 1,
s: 2,
m: 3
},
s: {
h: 1,
ms: 2,
m: 3
},
m: {
ms: 1,
s: 2,
h: 3
},
h: {
ms: 1,
s: 2,
m: 3
}
}
const getIn2: Test<typeof convertFunctionsMap> = ()=> {}
getIn2('ms', 'h');
·
Santiago Gelvez
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