import { ComponentType } from 'react'; import { Preview, Meta, Story } from 'storybook/internal/csf'; import { Args, DecoratorFunction, ArgsStoryFn, ComponentAnnotations, Renderer, StoryAnnotations } from 'storybook/internal/types'; import { c as Simplify, A as AddMocks, d as SetOptional } from './public-types-f2c70f25.js'; import { R as ReactRenderer } from './types-5617c98e.js'; /** Remove any index signatures from the given object type, so that only explicitly defined properties remain. Use-cases: - Remove overly permissive signatures from third-party types. This type was taken from this [StackOverflow answer](https://stackoverflow.com/a/68261113/420747). It relies on the fact that an empty object (`{}`) is assignable to an object with just an index signature, like `Record`, but not to an object with explicitly defined keys, like `Record<'foo' | 'bar', unknown>`. (The actual value type, `unknown`, is irrelevant and could be any type. Only the key type matters.) ``` const indexed: Record = {}; // Allowed const keyed: Record<'foo', unknown> = {}; // Error // => TS2739: Type '{}' is missing the following properties from type 'Record<"foo" | "bar", unknown>': foo, bar ``` Instead of causing a type error like the above, you can also use a [conditional type](https://www.typescriptlang.org/docs/handbook/2/conditional-types.html) to test whether a type is assignable to another: ``` type Indexed = {} extends Record ? '✅ `{}` is assignable to `Record`' : '❌ `{}` is NOT assignable to `Record`'; // => '✅ `{}` is assignable to `Record`' type Keyed = {} extends Record<'foo' | 'bar', unknown> ? "✅ `{}` is assignable to `Record<'foo' | 'bar', unknown>`" : "❌ `{}` is NOT assignable to `Record<'foo' | 'bar', unknown>`"; // => "❌ `{}` is NOT assignable to `Record<'foo' | 'bar', unknown>`" ``` Using a [mapped type](https://www.typescriptlang.org/docs/handbook/2/mapped-types.html#further-exploration), you can then check for each `KeyType` of `ObjectType`... ``` import type {RemoveIndexSignature} from 'type-fest'; type RemoveIndexSignature = { [KeyType in keyof ObjectType // Map each key of `ObjectType`... ]: ObjectType[KeyType]; // ...to its original value, i.e. `RemoveIndexSignature == Foo`. }; ``` ...whether an empty object (`{}`) would be assignable to an object with that `KeyType` (`Record`)... ``` import type {RemoveIndexSignature} from 'type-fest'; type RemoveIndexSignature = { [KeyType in keyof ObjectType // Is `{}` assignable to `Record`? as {} extends Record ? ... // ✅ `{}` is assignable to `Record` : ... // ❌ `{}` is NOT assignable to `Record` ]: ObjectType[KeyType]; }; ``` If `{}` is assignable, it means that `KeyType` is an index signature and we want to remove it. If it is not assignable, `KeyType` is a "real" key and we want to keep it. ``` import type {RemoveIndexSignature} from 'type-fest'; type RemoveIndexSignature = { [KeyType in keyof ObjectType as {} extends Record ? never // => Remove this `KeyType`. : KeyType // => Keep this `KeyType` as it is. ]: ObjectType[KeyType]; }; ``` @example ``` import type {RemoveIndexSignature} from 'type-fest'; interface Example { // These index signatures will be removed. [x: string]: any [x: number]: any [x: symbol]: any [x: `head-${string}`]: string [x: `${string}-tail`]: string [x: `head-${string}-tail`]: string [x: `${bigint}`]: string [x: `embedded-${number}`]: string // These explicitly defined keys will remain. foo: 'bar'; qux?: 'baz'; } type ExampleWithoutIndexSignatures = RemoveIndexSignature; // => { foo: 'bar'; qux?: 'baz' | undefined; } ``` @category Object */ type RemoveIndexSignature = { [KeyType in keyof ObjectType as {} extends Record ? never : KeyType]: ObjectType[KeyType]; }; /** Convert a union type to an intersection type using [distributive conditional types](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-8.html#distributive-conditional-types). Inspired by [this Stack Overflow answer](https://stackoverflow.com/a/50375286/2172153). @example ``` import type {UnionToIntersection} from 'type-fest'; type Union = {the(): void} | {great(arg: string): void} | {escape: boolean}; type Intersection = UnionToIntersection; //=> {the(): void; great(arg: string): void; escape: boolean}; ``` A more applicable example which could make its way into your library code follows. @example ``` import type {UnionToIntersection} from 'type-fest'; class CommandOne { commands: { a1: () => undefined, b1: () => undefined, } } class CommandTwo { commands: { a2: (argA: string) => undefined, b2: (argB: string) => undefined, } } const union = [new CommandOne(), new CommandTwo()].map(instance => instance.commands); type Union = typeof union; //=> {a1(): void; b1(): void} | {a2(argA: string): void; b2(argB: string): void} type Intersection = UnionToIntersection; //=> {a1(): void; b1(): void; a2(argA: string): void; b2(argB: string): void} ``` @category Type */ type UnionToIntersection = ( // `extends unknown` is always going to be the case and is used to convert the // `Union` into a [distributive conditional // type](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-8.html#distributive-conditional-types). Union extends unknown // The union type is used as the only argument to a function since the union // of function arguments is an intersection. ? (distributedUnion: Union) => void // This won't happen. : never // Infer the `Intersection` type since TypeScript represents the positional // arguments of unions of functions as an intersection of the union. ) extends ((mergedIntersection: infer Intersection) => void) ? Intersection : never; /** Do not use, use the definePreview exported from the framework instead */ declare function __definePreview(preview: ReactPreview['input']): ReactPreview; interface ReactPreview extends Preview { meta, TMetaArgs extends Partial>(meta: { render?: ArgsStoryFn; component?: ComponentType; decorators?: Decorators | Decorators[]; args?: TMetaArgs; } & Omit, 'decorators'>): ReactMeta<{ args: Simplify>>>; }, { args: Partial extends TMetaArgs ? {} : TMetaArgs; }>; } type DecoratorsArgs = UnionToIntersection ? TArgs : unknown>; interface ReactMeta> extends Meta { story & { render: () => ReactRenderer['storyResult']; }>(story: TInput): ReactStory; story, SetOptional>>>(story: TInput): ReactStory; } interface ReactStory extends Story { } export { ReactPreview, ReactStory, __definePreview };