37 lines
1.2 KiB
Plaintext
37 lines
1.2 KiB
Plaintext
import type {Merge} from './merge';
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/**
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Override existing properties of the given type. Similar to `Merge`, but enforces that the original type has the properties you want to override.
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This is useful when you want to override existing properties with a different type and make sure that these properties really exist in the original.
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@example
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```
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type Foo = {
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a: string
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b: string
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}
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type Bar = OverrideProperties<Foo, {b: number}>
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//=> {a: string, b: number}
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type Baz = OverrideProperties<Foo, {c: number}>
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// Error, type '{ c: number; }' does not satisfy the constraint '{ c: never; }'
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type Fizz = OverrideProperties<Foo, {b: number; c: number}>
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// Error, type '{ b: number; c: number; }' does not satisfy the constraint '{ b: number; c: never; }'
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```
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@category Object
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*/
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export type OverrideProperties<
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TOriginal,
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// This first bit where we use `Partial` is to enable autocomplete
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// and the second bit with the mapped type is what enforces that we don't try
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// to override properties that doesn't exist in the original type.
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TOverride extends Partial<Record<keyof TOriginal, unknown>> & {
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[Key in keyof TOverride]: Key extends keyof TOriginal
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? TOverride[Key]
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: never;
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},
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> = Merge<TOriginal, TOverride>;
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