npm install jotai-effect @form-atoms/list-atom
import { fromAtom, useForm, fieldAtom, InputField } from "form-atoms";
import { listAtom, List } from "@form-atoms/list-atom";
const environmentVariables = listAtom({
name: "environment",
value: [{ key: "GITHUB_SECRET", value: "<hash>" }],
fields: ({ key, value }) => ({
key: fieldAtom({ value: key }),
value: fieldAtom({ value }),
}),
});
const form = formAtom({ environmentVariables });
export const Form = () => {
const { submit } = useForm(form);
return (
<form onSubmit={submit(console.log)}>
<List atom={environmentVariables}>
{({ fields }) => (
<>
<InputField
atom={fields.key}
render={(props) => (
<>
<label>Variable Key</label>
<input {...props} />
</>
)}
/>
<InputField
atom={fields.value}
render={(props) => (
<>
<label>Variable Value</label>
<input {...props} />
</>
)}
/>
</>
)}
</List>
</form>
);
};| Atoms | Description |
|---|---|
listAtom() |
An atom that represents a list of form fields in a form. It manages state for the list, including the name, value, errors, dirty, validation and empty state. |
| Hooks | Description |
|---|---|
useListActions() |
A hook that returns a add, remove & move actions, that can be used to interact with the list atom state. |
useList() |
A hook that returns the list items ready to be rendred together with the list actions. |
| Components | Description |
|---|---|
<List> |
A component that render the individual items of listAtom with render props to render AddButton, RemoveButton and/or Empty slate. |
An atom that represents a list of form fields in a form. It manages state for the list, including the name, value, errors, dirty, validation and empty state.
| Name | Type | Required? | Description |
|---|---|---|---|
| config | ListAtomConfig<Fields, Value> |
Yes | The initial state and configuration of the field. |
export type ListAtomConfig<Fields extends FormFields, Value> = {
/**
* Optionally provide a name for the field that will be added
* prefixed to inner fields
* E.g. list name "contacts" and field name "email"
* will have scoped name for the 4th item "contacts[3].email"
*/
name?: string;
/**
* The initial array of values of the list
*/
value: Value[];
/**
* A function to initialize the fields for each of the initial values.
*/
fields: (value: Value) => Fields;
/**
* Error message the listAtom will have, when its items have nested errors.
* It will be one of errors returned by the `useFieldErrors()` hook.
*/
invalidItemError?: string;
/**
* A function that validates the value of the field any time
* one of its atoms changes. It must either return an array of
* string error messages or undefined. If it returns undefined,
* the validation is "skipped" and the current errors in state
* are retained.
*/
validate?: (state: {
/**
* A Jotai getter that can read other atoms
*/
get: Getter;
/**
* The current value of the field
*/
value: Value;
/**
* The dirty state of the field
*/
dirty: boolean;
/**
* The touched state of the field
*/
touched: boolean;
/**
* The event that caused the validation. Either:
*
* - `"change"` - The value of the field has changed
* - `"touch"` - The field has been touched
* - `"blur"` - The field has been blurred
* - `"submit"` - The form has been submitted
* - `"user"` - A user/developer has triggered the validation
*/
event: ValidateOn;
}) => void | string[] | Promise<void | string[]>;
};An extended FieldAtom:
export type ListAtom<Fields extends FormFields, Value> = ExtendFieldAtom<
Value[],
{
/**
* An atom indicating whether the list is empty.
*/
empty: Atom<boolean>;
/**
* A splitAtom() instance from jotai/utils.
* It handles adding, removing and moving of items in the list.
* @internal
*/
_splitList: WritableAtom<
PrimitiveAtom<ListItemForm<Fields>>[],
[SplitAtomAction<ListItemForm<Fields>>],
void
>;
/**
* An atom holding the list of forms of each item.
* @internal
*/
_formList: WritableAtom<
ListItemForm<Fields>[],
[typeof RESET | SetStateAction<ListItemForm<Fields>[]>],
void
>;
/**
* An atom holding the fields of the internal formAtom of each item.
* @internal
*/
_formFields: Atom<Fields[]>;
buildItem(): ListItemForm<Fields>;
}
>;A hook that returns a add, remove & move actions, that can be used to interact with the list atom state.
| Name | Type | Required? | Description |
|---|---|---|---|
| listAtom | ListAtom<Fields extends FormFields, Value> |
Yes | The atom that stores the list's state |
| options | UseAtomOptions |
No | Options that are forwarded to the useAtom, useAtomValue, and useSetAtom hooks |
export type UseListActions<Fields extends FormFields> = {
/**
* Removes the item from the list.
*
* @param item - An item from the listAtom's splitList array.
*/
remove: (item: ListItem<Fields>) => void;
/**
* Appends a new item to the list by default, when no 'before' position is used.
* Optionally the item can be initialized, with the 'fields' argument.
*
* @param before - An item from the listAtom's splitList array.
* @param fields - A custom initialized fieldAtoms matching the Fields shape of the list.
*/
add: (
before?: ListItem<Fields> | undefined,
fields?: Fields | undefined,
) => void;
/**
* Moves the item to the end of the list, or where specified when the 'before' is defined.
*
* @param item - A splitList item to be moved.
* @param before - A splitList item before which to place the moved item.
*/
move: (item: ListItem<Fields>, before?: ListItem<Fields> | undefined) => void;
};A hook that returns the list items ready to be rendred together with the list actions.
| Name | Type | Required? | Description |
|---|---|---|---|
| listAtom | ListAtom<Fields extends FormFields, Value> |
Yes | The atom that stores the list's state |
| options | UseAtomOptions |
No | Options that are forwarded to the useAtom, useAtomValue, and useSetAtom hooks |
export type UseList<Fields extends FormFields> = UseListActions<Fields> & {
/**
* Resolved value from the list.empty atom.
*/
isEmpty: boolean;
items: {
/**
* The item from the internal splitList.
*/
item: ListItem<Fields>;
/**
* Stable React key prop derived from atom id.
*/
key: string;
/**
* The form fields of the current item.
*/
fields: Fields;
/**
* A function to remove the current item from the list.
*/
remove: () => void;
/**
* A helper function to move the item to the previous index in the list.
*/
moveUp: () => void;
/**
* A helper function to move the item to the next index in the list.
*/
moveDown: () => void;
};
};| Name | Type | Required? | Description |
|---|---|---|---|
| atom | ListAtom<FormFields, Value> |
Yes | A list atom |
| children | (props: ListItemProps) => JSX.Element |
Yes | A render prop |
| initialValue | Value[] |
No | A value to (re)initialize the listAtom |
| RemoveButton | FunctionComponent<{remove: () => void}> |
no | A render prop receiving remove function for each individual list item |
| AddButton | FunctionComponent<{add: (fields?: Fields) => void}> |
No | A render prop to render a button adding new items to the end of the list |
| Empty | FunctionComponent |
No | A render prop to render a blank slate when there are no items in the list |
| store | AtomStore |
No | A Jotai store |
Your children render prop will receive the following props:
type ListItemProps<Fields extends FormFields> = {
/**
* The fields of current item, as returned from the builder function.
*/
fields: Fields;
/**
* The item from the internal splitList.
*/
item: ListItem<Fields>;
/**
* The index of the current item.
*/
index: number;
/**
* Total count of items in the list.
*/
count: number;
/**
* Append a new item to the end of the list.
* When called with current item, it will be prepend with a new item.
*/
add: (before?: ListItem<Fields>) => void;
/**
* Removes the current item.
*/
remove: () => void;
/**
* Moves the current item one slot up in the list.
* When called for the first item, the action is no-op.
*/
moveUp: () => void;
/**
* Moves the current item one slot down in the list.
* When called for the last item, the item moves to the start of the list.
*/
moveDown: () => void;
/**
* A component with an onClick handler bound to remove the current item from the list.
*/
RemoveButton: FunctionComponent;
};
MIT