React 中的状态管理可能很棘手，尤其是在处理复杂或嵌套的状态结构时。为了简化这一点，useCustomReducer 挂钩将 useReducer 的强大功能与灵活的 API 结合起来，以干净、声明的方式更新状态。该钩子支持原始状态、嵌套状态和数组状态，使其适用于广泛的用例。
在本文中，我们将探索 useCustomReducer 钩子及其用于管理 React 应用程序状态的核心方法。我们将介绍钩子的定义、其方法签名以及不同类型状态结构的详细使用示例。最后，您将深入了解如何使用 useCustomReducer 钩子来处理 React 组件中的复杂状态。
useCustomReducer 钩子是一个自定义的 React 钩子，它提供了一种简单而灵活的方法来管理复杂的状态结构。它将 useReducer 的优点与用于更新状态值的干净 API 结合起来。该钩子旨在处理各种类型的状态，包括原始值、对象、数组和嵌套数据结构。
以下是 useCustomReducer 钩子的概述：
核心方法:
状态结构： - 支持原始值（例如数字、字符串、布尔值）。 - 处理基于对象的状态结构（例如表单数据、用户配置文件）。 - 管理基于数组的状态结构（例如列表、集合）。
类型安全： - 使用 TypeScript 进行完全类型化，以实现可靠的开发和错误预防。
简单 API： - 提供更新、重置和合并状态值的直观方法。 - 支持动态状态变化的直接更新和回调函数。
import { useReducer, useCallback, useMemo } from "react";
type Primitive = boolean | string | number | Date | null | undefined;
type NestedObject = { [key: string]: Primitive | NestedObject | NestedArray };
type NestedArray = Array<Primitive | NestedObject>;
type State = Primitive | NestedObject | NestedArray;
type Action<T> =
| { type: "SET"; payload: Partial<T> | ((prevState: T) => Partial<T>) }
| { type: "RESET"; payload?: T }
| { type: "MERGE"; payload: Partial<T> };
function useCustomReducer<T extends State>(initialState: T) {
const reducer = useCallback(
(state: T, action: Action<T>): T => {
switch (action.type) {
case "SET":
const newPayload =
typeof action.payload === "function"
? action.payload(state)
: action.payload;
if (newPayload instanceof Date) {
return newPayload as T;
}
if (
typeof state === "object" &&
!Array.isArray(state) &&
state !== null
) {
return { ...state, ...newPayload };
}
return newPayload as T;
case "RESET":
return action.payload ?? initialState;
case "MERGE":
if (
typeof state === "object" &&
!Array.isArray(state) &&
state !== null
) {
return { ...state, ...action.payload };
}
return action.payload as T;
default:
throw new Error("Invalid action type");
}
},
[initialState]
);
const [state, dispatch] = useReducer(reducer, initialState);
const set = useCallback(
(payload: Partial<T> | ((prevState: T) => Partial<T>)) =>
dispatch({ type: "SET", payload }),
[]
);
const reset = useCallback(
(payload?: T) => dispatch({ type: "RESET", payload }),
[]
);
const merge = useCallback(
(payload: Partial<T>) => dispatch({ type: "MERGE", payload }),
[]
);
const memoizedState = useMemo(() => state, [state]);
return [memoizedState, { set, reset, merge }] as const;
}
export default useCustomReducer;
useCustomReducer 钩子是使用 React 中的 useReducer 钩子实现的。它定义了一个自定义减速器函数，用于处理不同类型的操作以更新、重置或合并状态值。该钩子提供了三个核心方法 set、reset 和 merge 来与状态交互。 set 方法可以接受具有新状态值的对象或回调函数来计算下一个状态。重置方法将状态恢复为其初始值，而合并方法将部分更新合并到现有状态。
这是在 React 组件中使用 useCustomReducer 挂钩来管理简单计数器状态的示例：
import useCustomReducer from "./use-custom-reducer";
import { faker } from "@faker-js/faker";
import { Button } from "@/components/ui/button";
export default function Use() {
const [formValues, { set, reset, merge }] = useCustomReducer({
name: faker.person.firstName(),
age: faker.number.int({ min: 18, max: 99 }),
address: {
street: faker.location.streetAddress(),
city: faker.location.city(),
state: faker.location.state(),
zip: faker.location.zipCode(),
},
hobbies: [faker.person.bio(), faker.person.bio(), faker.person.bio()],
});
const [bool, { set: setBool }] = useCustomReducer<boolean>(
faker.datatype.boolean()
);
const [num, { set: setNum }] = useCustomReducer(faker.number.int());
const [str, { set: setStr }] = useCustomReducer<string>(faker.lorem.word());
const [date, { set: setDate }] = useCustomReducer(faker.date.recent());
const [nil, { set: setNil }] = useCustomReducer(null);
const [undef, { set: setUndef }] = useCustomReducer(undefined);
const [arr, { set: setArr }] = useCustomReducer([
faker.number.int(),
faker.number.int(),
faker.number.int(),
]);
const [nestedArr, { set: setNestedArr }] = useCustomReducer([
faker.number.int(),
faker.lorem.word(),
{ three: faker.number.float() },
]);
const [obj, { set: setObj }] = useCustomReducer({
a: faker.number.int(),
b: faker.number.int(),
c: faker.number.int(),
});
const [nestedObj, { set: setNestedObj }] = useCustomReducer({
a: faker.number.int(),
b: faker.lorem.word(),
c: { three: faker.number.float() },
});
return (
<div className="p-4 space-y-6">
<h1 className="text-2xl font-bold">Use</h1>
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Form Values</h2>
<p className="text-gray-500">{JSON.stringify(formValues)}</p>
<Button onClick={() => set({ name: faker.person.firstName() })}>
Set Name
</Button>
<Button
onClick={() => set((prevState) => ({ age: prevState.age - 1 }))}
>
Decrement Age
</Button>
<Button
onClick={() => set((prevState) => ({ age: prevState.age + 1 }))}
>
Increment Age
</Button>
<Button
onClick={() =>
set((prevState) => ({
address: {
...prevState.address,
street: faker.location.streetAddress(),
},
}))
}
>
Set Street
</Button>
<Button onClick={() => reset()}>Reset</Button>
<Button
onClick={() => merge({ age: faker.number.int({ min: 18, max: 99 }) })}
>
Merge
</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Boolean Value</h2>
<p className="text-gray-500">{bool.toString()}</p>
<Button onClick={() => setBool(faker.datatype.boolean())}>
Set Bool
</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Number Value</h2>
<p className="text-gray-500">{num.toString()}</p>
<Button onClick={() => setNum(faker.number.int())}>Set Num</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">String Value</h2>
<p className="text-gray-500">{str}</p>
<Button onClick={() => setStr(faker.lorem.word())}>Set Str</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Date Value</h2>
<p className="text-gray-500">{JSON.stringify(date)}</p>
<Button onClick={() => setDate(faker.date.recent())}>Set Date</Button>
<Button onClick={() => setDate(new Date("2022-01-01"))}>
Set Date to 2022
</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Nil and Undefined</h2>
<p className="text-gray-500">{String(nil)}</p>
<Button onClick={() => setNil(null)}>Set Nil</Button>
<p className="text-gray-500">{String(undef)}</p>
<Button onClick={() => setUndef(undefined)}>Set Undef</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Array Value</h2>
<p className="text-gray-500">{arr.toString()}</p>
<Button
onClick={() =>
setArr([faker.number.int(), faker.number.int(), faker.number.int()])
}
>
Set Arr
</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Nested Array</h2>
<p className="text-gray-500">{JSON.stringify(nestedArr)}</p>
<Button
onClick={() =>
setNestedArr([
faker.number.int(),
faker.lorem.word(),
{ three: faker.number.float() },
])
}
>
Set Nested Arr
</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Object Value</h2>
<p className="text-gray-500">{JSON.stringify(obj)}</p>
<Button
onClick={() =>
setObj({
a: faker.number.int(),
b: faker.number.int(),
c: faker.number.int(),
})
}
>
Set Obj
</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Nested Object</h2>
<p className="text-gray-500">{JSON.stringify(nestedObj)}</p>
<Button
onClick={() =>
setNestedObj({
a: faker.number.int(),
b: faker.lorem.word(),
c: { three: faker.number.float() },
})
}
>
Set Nested Obj
</Button>
</div>
</div>
);
}
支持多种状态结构：处理基元、对象、数组和嵌套数据结构。
简单的API：
类型安全：使用 TypeScript 进行完全类型化，以实现可靠的开发。
useCustomReducer 钩子是一个用于管理复杂状态的自定义 React 钩子。它提供了三个核心方法 set、reset 和 merge 来处理原始、嵌套和基于数组的状态结构。以下是钩子及其方法的详细说明：
function useCustomReducer<T extends State>(
initialState: T
): [
T,
{
set: (payload: Partial<T> | ((prevState: T) => Partial<T>)) => void;
reset: (payload?: T) => void;
merge: (payload: Partial<T>) => void;
}
];
const [state, { set }] = useCustomReducer({ count: 0 });
set((prevState) => ({ count: prevState.count + 1 }));
reset(); // Resets to initial state.
reset({ name: "John", age: 25 }); // Resets to a new state.
merge({ city: "New York" }); // Adds or updates the 'city' field.
useCustomReducer 钩子用途广泛，可用于管理各种类型的状态结构。以下是一些示例来演示其在不同类型状态下的用法：
const initialState = 0;
const [count, { set, reset }] = useCustomReducer(initialState);
用法：
set((prevState) => prevState + 1);
reset();
set(10);
字符串：
const initialState = "Hello, World!";
const [message, { set, reset }] = useCustomReducer(initialState);
用法：
import { useReducer, useCallback, useMemo } from "react";
type Primitive = boolean | string | number | Date | null | undefined;
type NestedObject = { [key: string]: Primitive | NestedObject | NestedArray };
type NestedArray = Array<Primitive | NestedObject>;
type State = Primitive | NestedObject | NestedArray;
type Action<T> =
| { type: "SET"; payload: Partial<T> | ((prevState: T) => Partial<T>) }
| { type: "RESET"; payload?: T }
| { type: "MERGE"; payload: Partial<T> };
function useCustomReducer<T extends State>(initialState: T) {
const reducer = useCallback(
(state: T, action: Action<T>): T => {
switch (action.type) {
case "SET":
const newPayload =
typeof action.payload === "function"
? action.payload(state)
: action.payload;
if (newPayload instanceof Date) {
return newPayload as T;
}
if (
typeof state === "object" &&
!Array.isArray(state) &&
state !== null
) {
return { ...state, ...newPayload };
}
return newPayload as T;
case "RESET":
return action.payload ?? initialState;
case "MERGE":
if (
typeof state === "object" &&
!Array.isArray(state) &&
state !== null
) {
return { ...state, ...action.payload };
}
return action.payload as T;
default:
throw new Error("Invalid action type");
}
},
[initialState]
);
const [state, dispatch] = useReducer(reducer, initialState);
const set = useCallback(
(payload: Partial<T> | ((prevState: T) => Partial<T>)) =>
dispatch({ type: "SET", payload }),
[]
);
const reset = useCallback(
(payload?: T) => dispatch({ type: "RESET", payload }),
[]
);
const merge = useCallback(
(payload: Partial<T>) => dispatch({ type: "MERGE", payload }),
[]
);
const memoizedState = useMemo(() => state, [state]);
return [memoizedState, { set, reset, merge }] as const;
}
export default useCustomReducer;
import useCustomReducer from "./use-custom-reducer";
import { faker } from "@faker-js/faker";
import { Button } from "@/components/ui/button";
export default function Use() {
const [formValues, { set, reset, merge }] = useCustomReducer({
name: faker.person.firstName(),
age: faker.number.int({ min: 18, max: 99 }),
address: {
street: faker.location.streetAddress(),
city: faker.location.city(),
state: faker.location.state(),
zip: faker.location.zipCode(),
},
hobbies: [faker.person.bio(), faker.person.bio(), faker.person.bio()],
});
const [bool, { set: setBool }] = useCustomReducer<boolean>(
faker.datatype.boolean()
);
const [num, { set: setNum }] = useCustomReducer(faker.number.int());
const [str, { set: setStr }] = useCustomReducer<string>(faker.lorem.word());
const [date, { set: setDate }] = useCustomReducer(faker.date.recent());
const [nil, { set: setNil }] = useCustomReducer(null);
const [undef, { set: setUndef }] = useCustomReducer(undefined);
const [arr, { set: setArr }] = useCustomReducer([
faker.number.int(),
faker.number.int(),
faker.number.int(),
]);
const [nestedArr, { set: setNestedArr }] = useCustomReducer([
faker.number.int(),
faker.lorem.word(),
{ three: faker.number.float() },
]);
const [obj, { set: setObj }] = useCustomReducer({
a: faker.number.int(),
b: faker.number.int(),
c: faker.number.int(),
});
const [nestedObj, { set: setNestedObj }] = useCustomReducer({
a: faker.number.int(),
b: faker.lorem.word(),
c: { three: faker.number.float() },
});
return (
<div className="p-4 space-y-6">
<h1 className="text-2xl font-bold">Use</h1>
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Form Values</h2>
<p className="text-gray-500">{JSON.stringify(formValues)}</p>
<Button onClick={() => set({ name: faker.person.firstName() })}>
Set Name
</Button>
<Button
onClick={() => set((prevState) => ({ age: prevState.age - 1 }))}
>
Decrement Age
</Button>
<Button
onClick={() => set((prevState) => ({ age: prevState.age + 1 }))}
>
Increment Age
</Button>
<Button
onClick={() =>
set((prevState) => ({
address: {
...prevState.address,
street: faker.location.streetAddress(),
},
}))
}
>
Set Street
</Button>
<Button onClick={() => reset()}>Reset</Button>
<Button
onClick={() => merge({ age: faker.number.int({ min: 18, max: 99 }) })}
>
Merge
</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Boolean Value</h2>
<p className="text-gray-500">{bool.toString()}</p>
<Button onClick={() => setBool(faker.datatype.boolean())}>
Set Bool
</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Number Value</h2>
<p className="text-gray-500">{num.toString()}</p>
<Button onClick={() => setNum(faker.number.int())}>Set Num</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">String Value</h2>
<p className="text-gray-500">{str}</p>
<Button onClick={() => setStr(faker.lorem.word())}>Set Str</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Date Value</h2>
<p className="text-gray-500">{JSON.stringify(date)}</p>
<Button onClick={() => setDate(faker.date.recent())}>Set Date</Button>
<Button onClick={() => setDate(new Date("2022-01-01"))}>
Set Date to 2022
</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Nil and Undefined</h2>
<p className="text-gray-500">{String(nil)}</p>
<Button onClick={() => setNil(null)}>Set Nil</Button>
<p className="text-gray-500">{String(undef)}</p>
<Button onClick={() => setUndef(undefined)}>Set Undef</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Array Value</h2>
<p className="text-gray-500">{arr.toString()}</p>
<Button
onClick={() =>
setArr([faker.number.int(), faker.number.int(), faker.number.int()])
}
>
Set Arr
</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Nested Array</h2>
<p className="text-gray-500">{JSON.stringify(nestedArr)}</p>
<Button
onClick={() =>
setNestedArr([
faker.number.int(),
faker.lorem.word(),
{ three: faker.number.float() },
])
}
>
Set Nested Arr
</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Object Value</h2>
<p className="text-gray-500">{JSON.stringify(obj)}</p>
<Button
onClick={() =>
setObj({
a: faker.number.int(),
b: faker.number.int(),
c: faker.number.int(),
})
}
>
Set Obj
</Button>
</div>
<hr className="border-t border-gray-300" />
<div className="space-x-2 space-y-2">
<h2 className="text-lg font-semibold">Nested Object</h2>
<p className="text-gray-500">{JSON.stringify(nestedObj)}</p>
<Button
onClick={() =>
setNestedObj({
a: faker.number.int(),
b: faker.lorem.word(),
c: { three: faker.number.float() },
})
}
>
Set Nested Obj
</Button>
</div>
</div>
);
}
布尔值：
function useCustomReducer<T extends State>(
initialState: T
): [
T,
{
set: (payload: Partial<T> | ((prevState: T) => Partial<T>)) => void;
reset: (payload?: T) => void;
merge: (payload: Partial<T>) => void;
}
];
用法：
const [state, { set }] = useCustomReducer({ count: 0 });
set((prevState) => ({ count: prevState.count + 1 }));
reset(); // Resets to initial state.
reset({ name: "John", age: 25 }); // Resets to a new state.
merge({ city: "New York" }); // Adds or updates the 'city' field.
日期：
const initialState = 0;
const [count, { set, reset }] = useCustomReducer(initialState);
用法：
set((prevState) => prevState + 1);
reset();
set(10);
空和未定义状态：
const initialState = "Hello, World!";
const [message, { set, reset }] = useCustomReducer(initialState);
用法：
set("Hello, React!");
reset();
const initialState = false;
const [isToggled, { set, reset }] = useCustomReducer(initialState);
set((prevState) => !prevState);
用法：
reset();
set(true);
const initialState = new Date();
const [date, { set, reset }] = useCustomReducer(initialState);
set(new Date("2022-01-01"));
reset();
set(new Date("2023-01-01"));
const initialState: string | null = null;
const initialState: string | undefined = undefined;
const [value, { set, reset }] = useCustomReducer(initialState); // Implicitly infer the type.
const [value, { set, reset }] = useCustomReducer<string | undefined>(
initialState
); // Explicitly define the type.
用法：
set("New Value");
reset();
set("New Value");
const initialState = {
name: "John Doe",
age: 30,
address: {
street: "123 Main St",
city: "Sample City",
state: "CA",
},
};
const [formData, { set, reset, merge }] = useCustomReducer(initialState);
set({ name: "Jane Doe" });
嵌套数组的初始状态：
set((prevState) => ({
address: {
...prevState.address,
city: "New City",
},
}));
用法：
set({ name: "Jane Doe" });
merge({ address: { city: "New York" } });
merge({ phone: "123-456-7890" });
reset();
const initialState = [1, 2, 3, 4, 5];
const [numbers, { set, reset, merge }] = useCustomReducer(initialState);
set((prevState) => [...prevState, 6]);
用法：
set((prevState) => prevState.filter((item) => item !== 3));
reset();
set([10, 20, 30]);
merge([6, 7, 8]);
灵活的状态管理:
简单 API:
更简洁的代码：
类型安全:
动态更新：
useCustomReducer 钩子是一个强大的工具，用于管理 React 应用程序中的复杂状态结构。通过将 useReducer 的灵活性与用于更新状态的简单 API 相结合，该挂钩简化了状态管理并减少了样板代码。无论您处理原始值、嵌套对象还是数组，useCustomReducer 挂钩都提供了一种干净且声明性的方式来处理状态更改。在您的下一个项目中尝试一下，轻松体验多功能状态管理的好处。
以上是useCustomReducer Hook：多功能状态管理工具的详细内容。更多信息请关注PHP中文网其他相关文章！
