microsoft / microsoft/TypeScript

Spread operator in JSX causes loss of type information for inline functions defined outside the spread operator

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Bug Domain: JSX/TSX Help Wanted
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Description

Bug Report

When defining conditional types on a JSX component, using a spread operator causes loss of type information on inline functions while removing the spread operator resolves the issue.

🔎 Search Terms
  • "jsx spread"
  • "TS7006"
⏯ Playground Link

Playground link with relevant code

💻 Code

Given the following types and JSX:

/**
 * Either all properties are included, or none of them should be
 * @example
 * type Ex = AllOrNone<{ search: string; onSearchChange: (value: string) => void}>
 *
 * // Ok
 * const t1: Ex = {
 *   search: "hello",
 *   onSearchChange: (value) => console.log(value)
 * }
 *
 * // Error, needs onSearchChange
 * const t2: Ex = {
 *   search: "hello",
 * }
 *
 * // Error, needs search
 * const t3: Ex = {
 *   onSearchChange: (value) => console.log(value)
 * }
 */
export type AllOrNone<T> = T | { [K in keyof T]?: never };


export type OrderHistoryTableProps = {
  data: OrderRow[];
  noDataText?: string;
} & SortParams &
  FilterParams &
  SearchParams;

type SortParams = AllOrNone<{
  sorting: SortingState;
  onSortChange: (state: SortingState) => void;
}>;

type FilterParams = AllOrNone<{
  filter: ColumnFiltersState;
  onFilterChange: (state: ColumnFiltersState) => void;
}>;

type SearchParams = AllOrNone<{
  search: string;
  onSearchChange: (value: string) => void;
}>;

function OrderHistoryTable({
  data,
  noDataText = "No orders to display!",
  onFilterChange,
  onSortChange,
  sorting,
  filter,
  search,
  onSearchChange,
}: OrderHistoryTableProps): JSX.Element {
  ...
}

/* sorting, filter, and search are correct types */
<OrderHistoryTable
  data={rowData}
  {...{ sorting, filter, search }}
  onSortChange={onSortChange}
  onFilterChange={setFilter}
  onSearchChange={(value) => setSearch(value)} // TS7006: Parameter 'value' implicitly has an 'any' type.
/>

However, removing the spread operator resolves the issue:

<OrderHistoryTable
  data={rowData}
  sorting={sorting}
  filter={filter}
  search={search}
  onSortChange={onSortChange}
  onFilterChange={setFilter}
  onSearchChange={(value) => setSearch(value)}
/>
🙁 Actual behavior

While using the spread operator for other props, the inline function loses type information.

🙂 Expected behavior

Given that the values provided in the spread operator are the correct type, the arguments in the inline function should retain type information.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the linked CodeSandbox reproduction and the JSX example, focusing on contextual typing of the inline onSearchChange function when other props use a spread operator. Compare type-checking with and without the spread, then add a regression test showing that the callback parameter retains its expected type.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
42/100

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