基本概念

本页面介绍了 @tanstack/angular-form 库中使用的基本概念和术语。熟悉这些概念将帮助您更好地理解和使用该库。

表单实例 (Form Instance)

表单实例 (Form Instance) 是一个表示单个表单的对象,提供了操作表单的方法和属性。您可以使用 injectForm 函数创建表单实例。该函数接收一个包含 onSubmit 函数的对象,该函数在表单提交时被调用。

typescript
const form = injectForm({
  onSubmit: async ({ value }) => {
    // 处理表单数据
    console.log(value)
  },
})
const form = injectForm({
  onSubmit: async ({ value }) => {
    // 处理表单数据
    console.log(value)
  },
})

字段 (Field)

字段 (Field) 表示单个表单输入元素,例如文本输入框或复选框。字段通过 tanstackField 指令创建。该指令接收一个 name 属性,该属性应与表单默认值中的键匹配。它还暴露了一个名为 field 的指令内部实例,应通过模板变量访问字段内部状态。

示例:

html
<ng-container [tanstackField]="form" name="firstName" #firstName="field">
  <input
    [value]="firstName.api.state.value"
    (blur)="firstName.api.handleBlur()"
    (input)="firstName.api.handleChange($any($event).target.value)"
  />
</ng-container>
<ng-container [tanstackField]="form" name="firstName" #firstName="field">
  <input
    [value]="firstName.api.state.value"
    (blur)="firstName.api.handleBlur()"
    (input)="firstName.api.handleChange($any($event).target.value)"
  />
</ng-container>

字段状态 (Field State)

每个字段都有自己的状态 (Field State),包括当前值、验证状态、错误消息和其他元数据。您可以通过 fieldApi.state 属性访问字段状态。

示例:

tsx
const {
  value,
  meta: { errors, isValidating },
} = field.state
const {
  value,
  meta: { errors, isValidating },
} = field.state

有三种字段状态可以非常直观地反映用户与字段的交互情况:当用户点击/聚焦到字段时,字段状态为 "touched";在用户修改值之前,字段状态为 "pristine";值被修改后,字段状态变为 "dirty"。您可以通过 isTouchedisPristineisDirty 标志来检查这些状态,如下所示。

tsx
const { isTouched, isPristine, isDirty } = field.state.meta
const { isTouched, isPristine, isDirty } = field.state.meta

字段状态

字段 API (Field API)

字段 API (Field API) 是一个对象,在创建字段时通过 tanstackField.api 属性访问。它提供了操作字段状态的方法。

示例:

angular-html
<input
  [value]="fieldName.api.state.value"
  (blur)="fieldName.api.handleBlur()"
  (input)="fieldName.api.handleChange($any($event).target.value)"
/>
<input
  [value]="fieldName.api.state.value"
  (blur)="fieldName.api.handleBlur()"
  (input)="fieldName.api.handleChange($any($event).target.value)"
/>

验证 (Validation)

@tanstack/angular-form 开箱即用地支持同步和异步验证。验证函数可以通过 validators 属性传递给 tanstackField 指令。

示例:

angular-ts
@Component({
  selector: 'app-root',
  standalone: true,
  imports: [TanStackField],
  template: `
    <ng-container [tanstackField]="form" name="firstName" #firstName="field">
      <input
        [value]="firstName.api.state.value"
        (blur)="firstName.api.handleBlur()"
        (input)="firstName.api.handleChange($any($event).target.value)"
      />
    </ng-container>
  `,
})
export class AppComponent {
  firstNameValidator: FieldValidateFn<any, any, string, any> = ({
                                                                       value,
                                                                     }) =>
    !value
      ? '必须填写名字'
      : value.length < 3
        ? '名字至少需要 3 个字符'
        : undefined

  firstNameAsyncValidator: FieldValidateAsyncFn<any, string, any> =
    async ({ value }) => {
      await new Promise((resolve) => setTimeout(resolve, 1000))
      return value.includes('error') && '名字中不能包含 "error"'
    }

  form = injectForm({
    defaultValues: {
      firstName: '',
    },
    onSubmit({ value }) {
      console.log(value)
    },
  })
}
@Component({
  selector: 'app-root',
  standalone: true,
  imports: [TanStackField],
  template: `
    <ng-container [tanstackField]="form" name="firstName" #firstName="field">
      <input
        [value]="firstName.api.state.value"
        (blur)="firstName.api.handleBlur()"
        (input)="firstName.api.handleChange($any($event).target.value)"
      />
    </ng-container>
  `,
})
export class AppComponent {
  firstNameValidator: FieldValidateFn<any, any, string, any> = ({
                                                                       value,
                                                                     }) =>
    !value
      ? '必须填写名字'
      : value.length < 3
        ? '名字至少需要 3 个字符'
        : undefined

  firstNameAsyncValidator: FieldValidateAsyncFn<any, string, any> =
    async ({ value }) => {
      await new Promise((resolve) => setTimeout(resolve, 1000))
      return value.includes('error') && '名字中不能包含 "error"'
    }

  form = injectForm({
    defaultValues: {
      firstName: '',
    },
    onSubmit({ value }) {
      console.log(value)
    },
  })
}

使用标准模式库验证 (Validation with Standard Schema Libraries)

除了手动编写的验证选项外,我们还支持 标准模式 (Standard Schema) 规范。

您可以使用实现该规范的任何库定义模式,并将其传递给表单或字段验证器。

支持的库包括:

示例:

angular-ts
import { z } from 'zod'

@Component({
  selector: 'app-root',
  standalone: true,
  imports: [TanStackField],
  template: `
    <ng-container
      [tanstackField]="form"
      name="firstName"
      [validators]="{
        onChange: z.string().min(3, '名字至少需要 3 个字符'),
        onChangeAsyncDebounceMs: 500,
        onChangeAsync: firstNameAsyncValidator
      }"
      #firstName="field"
    >
      <!-- ... -->
    </ng-container>
  `,
})
export class AppComponent {
  firstNameAsyncValidator = z.string().refine(
    async (value) => {
      await new Promise((resolve) => setTimeout(resolve, 1000))
      return !value.includes('error')
    },
    {
      message: "名字中不能包含 'error'",
    },
  )

  form = injectForm({
    defaultValues: {
      firstName: '',
    },
    onSubmit({ value }) {
      // 处理表单数据
      console.log(value)
    },
  })

  z = z
}
import { z } from 'zod'

@Component({
  selector: 'app-root',
  standalone: true,
  imports: [TanStackField],
  template: `
    <ng-container
      [tanstackField]="form"
      name="firstName"
      [validators]="{
        onChange: z.string().min(3, '名字至少需要 3 个字符'),
        onChangeAsyncDebounceMs: 500,
        onChangeAsync: firstNameAsyncValidator
      }"
      #firstName="field"
    >
      <!-- ... -->
    </ng-container>
  `,
})
export class AppComponent {
  firstNameAsyncValidator = z.string().refine(
    async (value) => {
      await new Promise((resolve) => setTimeout(resolve, 1000))
      return !value.includes('error')
    },
    {
      message: "名字中不能包含 'error'",
    },
  )

  form = injectForm({
    defaultValues: {
      firstName: '',
    },
    onSubmit({ value }) {
      // 处理表单数据
      console.log(value)
    },
  })

  z = z
}

响应式 (Reactivity)

@tanstack/angular-form 提供了一种通过 injectStore(this.form, selector) 订阅表单和字段状态变化的方式。

示例:

typescript
import { injectForm, injectStore } from '@tanstack/angular-form'

@Component(/*...*/)
class AppComponent {
  form = injectForm(/*...*/)
  canSubmit = injectStore(this.form, (state) => state.canSubmit)
  isSubmitting = injectStore(this.form, (state) => state.isSubmitting)
}
import { injectForm, injectStore } from '@tanstack/angular-form'

@Component(/*...*/)
class AppComponent {
  form = injectForm(/*...*/)
  canSubmit = injectStore(this.form, (state) => state.canSubmit)
  isSubmitting = injectStore(this.form, (state) => state.isSubmitting)
}

监听器 (Listeners)

@tanstack/angular-form 允许您响应特定触发器并"监听"它们以执行副作用。

示例:

angular-ts
@Component({
  selector: 'app-root',
  standalone: true,
  imports: [TanStackField],
  template: `
    <ng-container
      [tanstackField]="form"
      name="country"
      [listeners]="{
        onChange: onCountryChange
      }"
      #country="field"
    ></ng-container>
  `,
})

...

onCountryChange: FieldListenerFn<any, any, any, any, string> = ({
    value,
  }) => {
    console.log(`国家已更改为: ${value}, 重置省份`)
    this.form.setFieldValue('province', '')
  }
@Component({
  selector: 'app-root',
  standalone: true,
  imports: [TanStackField],
  template: `
    <ng-container
      [tanstackField]="form"
      name="country"
      [listeners]="{
        onChange: onCountryChange
      }"
      #country="field"
    ></ng-container>
  `,
})

...

onCountryChange: FieldListenerFn<any, any, any, any, string> = ({
    value,
  }) => {
    console.log(`国家已更改为: ${value}, 重置省份`)
    this.form.setFieldValue('province', '')
  }

更多信息请参阅 监听器

数组字段 (Array Fields)

数组字段 (Array Fields) 允许您管理表单中的值列表,例如爱好列表。您可以使用 tanstackField 指令创建数组字段。

在处理数组字段时,可以使用字段的 pushValueremoveValueswapValues 方法来添加、删除和交换数组中的值。

示例:

angular-ts
@Component({
  selector: 'app-root',
  standalone: true,
  imports: [TanStackField],
  template: `
    <ng-container [tanstackField]="form" name="hobbies" #hobbies="field">
      <div>
        爱好
        <div>
          @if (!hobbies.api.state.value.length) {
            未找到爱好
          }
          @for (_ of hobbies.api.state.value; track $index) {
            <div>
              <ng-container
                [tanstackField]="form"
                [name]="getHobbyName($index)"
                #hobbyName="field"
              >
                <div>
                  <label [for]="hobbyName.api.name">名称:</label>
                  <input
                    [id]="hobbyName.api.name"
                    [name]="hobbyName.api.name"
                    [value]="hobbyName.api.state.value"
                    (blur)="hobbyName.api.handleBlur()"
                    (input)="
                      hobbyName.api.handleChange($any($event).target.value)
                    "
                  />
                  <button
                    type="button"
                    (click)="hobbies.api.removeValue($index)"
                  >
                    X
                  </button>
                </div>
              </ng-container>
              <ng-container
                [tanstackField]="form"
                [name]="getHobbyDesc($index)"
                #hobbyDesc="field"
              >
                <div>
                  <label [for]="hobbyDesc.api.name">描述:</label>
                  <input
                    [id]="hobbyDesc.api.name"
                    [name]="hobbyDesc.api.name"
                    [value]="hobbyDesc.api.state.value"
                    (blur)="hobbyDesc.api.handleBlur()"
                    (input)="
                      hobbyDesc.api.handleChange($any($event).target.value)
                    "
                  />
                </div>
              </ng-container>
            </div>
          }
        </div>
        <button type="button" (click)="hobbies.api.pushValue(defaultHobby)">
          添加爱好
        </button>
      </div>
    </ng-container>
  `,
})
export class AppComponent {
  defaultHobby = {
    name: '',
    description: '',
    yearsOfExperience: 0,
  }

  getHobbyName = (idx: number) => `hobbies[${idx}].name` as const;
  getHobbyDesc = (idx: number) => `hobbies[${idx}].description` as const;

  form = injectForm({
    defaultValues: {
      hobbies: [] as Array<{
        name: string
        description: string
        yearsOfExperience: number
      }>,
    },
    onSubmit({ value }) {
      alert(JSON.stringify(value))
    },
  })
}
@Component({
  selector: 'app-root',
  standalone: true,
  imports: [TanStackField],
  template: `
    <ng-container [tanstackField]="form" name="hobbies" #hobbies="field">
      <div>
        爱好
        <div>
          @if (!hobbies.api.state.value.length) {
            未找到爱好
          }
          @for (_ of hobbies.api.state.value; track $index) {
            <div>
              <ng-container
                [tanstackField]="form"
                [name]="getHobbyName($index)"
                #hobbyName="field"
              >
                <div>
                  <label [for]="hobbyName.api.name">名称:</label>
                  <input
                    [id]="hobbyName.api.name"
                    [name]="hobbyName.api.name"
                    [value]="hobbyName.api.state.value"
                    (blur)="hobbyName.api.handleBlur()"
                    (input)="
                      hobbyName.api.handleChange($any($event).target.value)
                    "
                  />
                  <button
                    type="button"
                    (click)="hobbies.api.removeValue($index)"
                  >
                    X
                  </button>
                </div>
              </ng-container>
              <ng-container
                [tanstackField]="form"
                [name]="getHobbyDesc($index)"
                #hobbyDesc="field"
              >
                <div>
                  <label [for]="hobbyDesc.api.name">描述:</label>
                  <input
                    [id]="hobbyDesc.api.name"
                    [name]="hobbyDesc.api.name"
                    [value]="hobbyDesc.api.state.value"
                    (blur)="hobbyDesc.api.handleBlur()"
                    (input)="
                      hobbyDesc.api.handleChange($any($event).target.value)
                    "
                  />
                </div>
              </ng-container>
            </div>
          }
        </div>
        <button type="button" (click)="hobbies.api.pushValue(defaultHobby)">
          添加爱好
        </button>
      </div>
    </ng-container>
  `,
})
export class AppComponent {
  defaultHobby = {
    name: '',
    description: '',
    yearsOfExperience: 0,
  }

  getHobbyName = (idx: number) => `hobbies[${idx}].name` as const;
  getHobbyDesc = (idx: number) => `hobbies[${idx}].description` as const;

  form = injectForm({
    defaultValues: {
      hobbies: [] as Array<{
        name: string
        description: string
        yearsOfExperience: number
      }>,
    },
    onSubmit({ value }) {
      alert(JSON.stringify(value))
    },
  })
}

这些是 @tanstack/angular-form 库中使用的基本概念和术语。理解这些概念将帮助您更高效地使用该库,轻松创建复杂的表单。

Subscribe to Bytes

Your weekly dose of JavaScript news. Delivered every Monday to over 100,000 devs, for free.

Bytes

No spam. Unsubscribe at any time.