英文:
Righthand side of Typescript intersection type is lost when mapping over array of that type
问题
In the provided code, when using Array.map on a collection of objects of MyType, TypeScript loses the right-hand side of the intersection type ({value: string}). However, when looping over the same collection with for ... of, TypeScript correctly tracks the types. This behavior might be due to how TypeScript infers types within the context of Array.map.
英文:
In the following code, when I try to use Array.map on a collection of objects of MyType, Typescript loses the right hand side of the intersection type ({value: string}). However, when I loop over the same collection with for ... of it tracks the types correctly. What's happening here?
(Typescript 5.0.2)
type MyType = {
containers: {
name: string;
}[] & {
value: string;
}[]
}
const data: MyType = {
containers: [{
name: "name",
value: "ddd",
}]
}
for (const container of data.containers) {
// This is fine
const { name, value } = container;
}
data.containers.map(container => {
// Property 'value' does not exist on type '{ name: string; }'.(2339)
const { name, value } = container;
})
答案1
得分: 2
The way myType is defined it looks like an intersection of two arrays. Instead, you want a single array which can hold objects with both properties name and value.
Change myType to:
type MyType = {
containers: ({
name: string;
} & {
value: string;
})[]
}
英文:
The way myType is defined it looks like an intersection of two arrays. Iinstead you want a single array which can hold object with both property name and value .
Change myType to
type MyType = {
containers: ({
name: string;
} & {
value: string;
})[]
}
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