--- name: react description: React framework for building user interfaces. Use for React components, hooks, state management, JSX, and modern frontend development. --- # React Skill Comprehensive assistance with react development, generated from official documentation. ## When to Use This Skill This skill should be triggered when: - Working with react - Asking about react features or APIs - Implementing react solutions - Debugging react code - Learning react best practices ## Quick Reference ### Common Patterns **Pattern 1:** API ReferenceComponentsThe built-in browser component lets you render different kinds of form inputs. Reference Usage Displaying inputs of different types Providing a label for an input Providing an initial value for an input Reading the input values when submitting a form Controlling an input with a state variable Optimizing re-rendering on every keystroke Troubleshooting My text input doesn’t update when I type into it My checkbox doesn’t update when I click on it My input caret jumps to the beginning on every keystroke I’m getting an error: “A component is changing an uncontrolled input to be controlled” Reference To display an input, render the built-in browser component. See more examples below. Props supports all common element props. formAction: A string or function. Overrides the parent

for type="submit" and type="image". When a URL is passed to action the form will behave like a standard HTML form. When a function is passed to formAction the function will handle the form submission. See . You can make an input controlled by passing one of these props: checked: A boolean. For a checkbox input or a radio button, controls whether it is selected. value: A string. For a text input, controls its text. (For a radio button, specifies its form data.) When you pass either of them, you must also pass an onChange handler that updates the passed value. These props are only relevant for uncontrolled inputs: defaultChecked: A boolean. Specifies the initial value for type="checkbox" and type="radio" inputs. defaultValue: A string. Specifies the initial value for a text input. These props are relevant both for uncontrolled and controlled inputs: accept: A string. Specifies which filetypes are accepted by a type="file" input. alt: A string. Specifies the alternative image text for a type="image" input. capture: A string. Specifies the media (microphone, video, or camera) captured by a type="file" input. autoComplete: A string. Specifies one of the possible autocomplete behaviors. autoFocus: A boolean. If true, React will focus the element on mount. dirname: A string. Specifies the form field name for the element’s directionality. disabled: A boolean. If true, the input will not be interactive and will appear dimmed. children: does not accept children. form: A string. Specifies the id of the this input belongs to. If omitted, it’s the closest parent form. formAction: A string. Overrides the parent for type="submit" and type="image". formEnctype: A string. Overrides the parent for type="submit" and type="image". formMethod: A string. Overrides the parent for type="submit" and type="image". formNoValidate: A string. Overrides the parent for type="submit" and type="image". formTarget: A string. Overrides the parent for type="submit" and type="image". height: A string. Specifies the image height for type="image". list: A string. Specifies the id of the with the autocomplete options. max: A number. Specifies the maximum value of numerical and datetime inputs. maxLength: A number. Specifies the maximum length of text and other inputs. min: A number. Specifies the minimum value of numerical and datetime inputs. minLength: A number. Specifies the minimum length of text and other inputs. multiple: A boolean. Specifies whether multiple values are allowed for changes. React extends the onSelect event to also fire for empty selection and on edits (which may affect the selection). onSelectCapture: A version of onSelect that fires in the capture phase. pattern: A string. Specifies the pattern that the value must match. placeholder: A string. Displayed in a dimmed color when the input value is empty. readOnly: A boolean. If true, the input is not editable by the user. required: A boolean. If true, the value must be provided for the form to submit. size: A number. Similar to setting width, but the unit depends on the control. src: A string. Specifies the image source for a type="image" input. step: A positive number or an 'any' string. Specifies the distance between valid values. type: A string. One of the input types. width: A string. Specifies the image width for a type="image" input. Caveats Checkboxes need checked (or defaultChecked), not value (or defaultValue). If a text input receives a string value prop, it will be treated as controlled. If a checkbox or a radio button receives a boolean checked prop, it will be treated as controlled. An input can’t be both controlled and uncontrolled at the same time. An input cannot switch between being controlled or uncontrolled over its lifetime. Every controlled input needs an onChange event handler that synchronously updates its backing value. Usage Displaying inputs of different types To display an input, render an component. By default, it will be a text input. You can pass type="checkbox" for a checkbox, type="radio" for a radio button, or one of the other input types. App.jsApp.jsReloadClearForkexport default function MyForm() { return ( <> Text input: <\/label>

Checkbox: <\/label>

Radio buttons: Option 1 <\/label> Option 2 <\/label> Option 3 <\/label> <\/p> <\/> ); } Show more Providing a label for an input Typically, you will place every inside a tag. This tells the browser that this label is associated with that input. When the user clicks the label, the browser will automatically focus the input. It’s also essential for accessibility: a screen reader will announce the label caption when the user focuses the associated input. If you can’t nest into a , associate them by passing the same ID to and . To avoid conflicts between multiple instances of one component, generate such an ID with useId. App.jsApp.jsReloadClearForkimport { useId } from 'react'; export default function Form() { const ageInputId = useId(); return ( <> Your first name: <\/label>

Your age:<\/label> <\/> ); } Show more Providing an initial value for an input You can optionally specify the initial value for any input. Pass it as the defaultValue string for text inputs. Checkboxes and radio buttons should specify the initial value with the defaultChecked boolean instead. App.jsApp.jsReloadClearForkexport default function MyForm() { return ( <> Text input: <\/label>

Checkbox: <\/label>

Radio buttons: Option 1 <\/label> Option 2 <\/label> Option 3 <\/label> <\/p> <\/> ); } Show more Reading the input values when submitting a form Add a around your inputs with a