This JSX tag's 'children' prop expects type 'string' which requires multiple children, but only a single child was provided

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#61,692 opened on May 12, 2025 5 comments 2 reactions 0 assignees View on GitHub

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Description

### 🔎 Search Terms

This JSX tag's 'children' prop expects type 'string' which requires multiple children, but only a single child was provided. ts(2745)
ts2745

### 🕗 Version & Regression Information

- Reproducible in 5.0.3 - 5.8.3
- The error message was different in 4.9.5 and below: "Property 'children' is missing in type '{}' but required in type '{ children: string; }'"

### ⏯ Playground Link

https://www.typescriptlang.org/play/?target=99&isolatedModules=true&ts=5.8.3#code/MYewdgzgLgBASgUwIbFgXhgb2AJ2VBAUQBsEBbBMKAGhgDEckBzCqgXwCgOB6bmAFQAWASwgwAUgGUAGjCjMA5GIXARxACZ4wCmAAccIXTAQAPXQlRioAT3MwlUHMLBMdAdxGqYeAI4BXYTwxMj9iKGFdUhhVYQ0tWgAjP1hwYmsYJBgIZyYomI0YNyQxfRAAN2F1BHUAOigIAAoAJgB2ABYAVgBKDlBIEFIa4hAmBoAeSUccgGE1TUoAPkzoJxcx7knVplnY+bAFroBuDgAzPzBUYXAYTZm5rQbMaPvKGDYALixn3a1PlZy3l0sBwYN4EFA-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-Ue0ii11Ds-4XDeEGODYIA

### 💻 Code

```tsx
const React = {createElement, Fragment}

// This JSX tag's 'children' prop expects type 'string' which requires multiple children, but only a single child was provided.ts(2745)
console.log(a string);
function StringChildren({ children }: { children: string }) {
return children;
}

// Works fine without children
console.log();
function NoChildren() {
// Fragment works fine
return <>a string;
}

// I don't know if this is related:
// JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists.ts(7026)
console.log(

);

// JSX typing is based fully on React 19 typings, but simplified to minimal reproducible example
// Exactly the same error occurs with React typings
// (https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/react/index.d.ts)
export declare function createElement(
sel: any,
data?: any,
text?: any
): JSX.Element;

export declare const Fragment: (props: {
children?: JSX.Element;
}) => JSX.Element;

export namespace JSX {
export type Element =
| string
| number
| bigint
| Iterable
| boolean
| null
| undefined;
export interface ElementAttributesProperty {}
export interface ElementChildrenAttribute { children?: Element;}
export interface IntrinsicAttributes {}
export interface IntrinsicElements { div: { id?: string };}
}
```

### 🙁 Actual behavior

Calling JSX component that accepts `string` children type emits the following error:
> This JSX tag's 'children' prop expects type 'string' which requires multiple children, but only a single child was provided.ts(2745)

### 🙂 Expected behavior

No error should be emitted

### Additional information about the issue

**The exact same error is reproducible with official React 19 typings**. See tiny reproduction repository: https://github.com/maxpatiiuk/typescript-react-19-jsx-bug

---

Looking at https://github.com/microsoft/TypeScript/blob/main/src/compiler/checker.ts, the error is triggered by the following check:

```ts
// Line 21585:
else if (!isTypeRelatedTo(getIndexedAccessType(source, childrenNameType), childrenTargetType, relation)) {
// arity mismatch
result = true;
const diag = error(
containingElement.openingElement.tagName,
Diagnostics.This_JSX_tag_s_0_prop_expects_type_1_which_requires_multiple_children_but_only_a_single_child_was_provided,
childrenPropName,
typeToString(childrenTargetType),
);
if (errorOutputContainer && errorOutputContainer.skipLogging) {
(errorOutputContainer.errors || (errorOutputContainer.errors = [])).push(diag);
}
}
```

It appears that `getIndexedAccessType(source, childrenNameType)` tries to get the indexed type of `string`, which returns `unknown` type, which is not considered related to `string` type.

---

Potentially related to https://github.com/microsoft/TypeScript/issues/60572, however the suggested workaround in that issue is not working.

Contributor guide

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First steps

Read the whole issue, then the project's contributing guide.
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Open a pull request that references the issue number.

Research direction

Start with the minimal reproduction in the Playground or the linked repository, then read the JSX children-checking path in src/compiler/checker.ts around the getIndexedAccessType check near line 21585. Verify the behavior with the provided StringChildren example and related React 19 typings; done means the valid single string child no longer emits ts(2745).

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: 45/100