Reactjs - 表单输入验证

Question

我的联系方式如下，

<form name="contactform" onSubmit={this.contactSubmit.bind(this)}>
  <div className="col-md-6">
    <fieldset>
      <input ref="name" type="text" size="30" placeholder="Name"/>
      <br/>
      <input refs="email" type="text" size="30" placeholder="Email"/>
      <br/>
      <input refs="phone" type="text" size="30" placeholder="Phone"/>
      <br/>
      <input refs="address" type="text" size="30" placeholder="Address"/>
      <br/>
    </fieldset>
  </div>
  <div className="col-md-6">
    <fieldset>
      <textarea refs="message" cols="40" rows="20"
                className="comments" placeholder="Message"/>
    </fieldset>
  </div>
  <div className="col-md-12">
    <fieldset>
      <button className="btn btn-lg pro" id="submit"
              value="Submit">Send Message</button>
    </fieldset>
  </div>
</form>

需要为所有字段添加验证。谁能帮我在这个反应表单中添加验证？

Answer 1

你应该避免使用 refs，你可以使用 onChange 函数。

每次更改时，更新已更改字段的状态。

然后您可以轻松检查该字段是否为空或其他任何您想要的。

你可以这样做：

class Test extends React.Component {
  constructor(props) {
    super(props);

    this.state = {
      fields: {},
      errors: {},
    };
  }

  handleValidation() {
    let fields = this.state.fields;
    let errors = {};
    let formIsValid = true;

    //Name
    if (!fields["name"]) {
      formIsValid = false;
      errors["name"] = "Cannot be empty";
    }

    if (typeof fields["name"] !== "undefined") {
      if (!fields["name"].match(/^[a-zA-Z]+$/)) {
        formIsValid = false;
        errors["name"] = "Only letters";
      }
    }

    //Email
    if (!fields["email"]) {
      formIsValid = false;
      errors["email"] = "Cannot be empty";
    }

    if (typeof fields["email"] !== "undefined") {
      let lastAtPos = fields["email"].lastIndexOf("@");
      let lastDotPos = fields["email"].lastIndexOf(".");

      if (
        !(
          lastAtPos < lastDotPos &&
          lastAtPos > 0 &&
          fields["email"].indexOf("@@") == -1 &&
          lastDotPos > 2 &&
          fields["email"].length - lastDotPos > 2
        )
      ) {
        formIsValid = false;
        errors["email"] = "Email is not valid";
      }
    }

    this.setState({ errors: errors });
    return formIsValid;
  }

  contactSubmit(e) {
    e.preventDefault();

    if (this.handleValidation()) {
      alert("Form submitted");
    } else {
      alert("Form has errors.");
    }
  }

  handleChange(field, e) {
    let fields = this.state.fields;
    fields[field] = e.target.value;
    this.setState({ fields });
  }

  render() {
    return (
      <div>
        <form
          name="contactform"
          className="contactform"
          onSubmit={this.contactSubmit.bind(this)}
        >
          <div className="col-md-6">
            <fieldset>
              <input
                ref="name"
                type="text"
                size="30"
                placeholder="Name"
                onChange={this.handleChange.bind(this, "name")}
                value={this.state.fields["name"]}
              />
              <span style={{ color: "red" }}>{this.state.errors["name"]}</span>
              <br />
              <input
                refs="email"
                type="text"
                size="30"
                placeholder="Email"
                onChange={this.handleChange.bind(this, "email")}
                value={this.state.fields["email"]}
              />
              <span style={{ color: "red" }}>{this.state.errors["email"]}</span>
              <br />
              <input
                refs="phone"
                type="text"
                size="30"
                placeholder="Phone"
                onChange={this.handleChange.bind(this, "phone")}
                value={this.state.fields["phone"]}
              />
              <br />
              <input
                refs="address"
                type="text"
                size="30"
                placeholder="Address"
                onChange={this.handleChange.bind(this, "address")}
                value={this.state.fields["address"]}
              />
              <br />
            </fieldset>
          </div>
        </form>
      </div>
    );
  }
}

React.render(<Test />, document.getElementById("container"));
    

在此示例中，我仅对电子邮件和姓名进行了验证，但您知道如何进行。其余的你可以自己做。

也许有更好的方法，但你会明白的。

Here is fiddle.

希望这会有所帮助。

Answer 2

试试这个，例如， 以下输入标签中的必需属性将确保名称字段不应提交为空。

<input type="text" placeholder="Your Name" required />

Answer 3

我已获取您的代码并使用库 react-form-with-constraints: https://codepen.io/tkrotoff/pen/LLraZp 对其进行了修改

const {
  FormWithConstraints,
  FieldFeedbacks,
  FieldFeedback
} = ReactFormWithConstraints;

class Form extends React.Component {
  handleChange = e => {
    this.form.validateFields(e.target);
  }

  contactSubmit = e => {
    e.preventDefault();

    this.form.validateFields();

    if (!this.form.isValid()) {
      console.log('form is invalid: do not submit');
    } else {
      console.log('form is valid: submit');
    }
  }

  render() {
    return (
      <FormWithConstraints
        ref={form => this.form = form}
        onSubmit={this.contactSubmit}
        noValidate>

        <div className="col-md-6">
          <input name="name" size="30" placeholder="Name"
                 required onChange={this.handleChange}
                 className="form-control" />
          <FieldFeedbacks for="name">
            <FieldFeedback when="*" />
          </FieldFeedbacks>

          <input type="email" name="email" size="30" placeholder="Email"
                 required onChange={this.handleChange}
                 className="form-control" />
          <FieldFeedbacks for="email">
            <FieldFeedback when="*" />
          </FieldFeedbacks>

          <input name="phone" size="30" placeholder="Phone"
                 required onChange={this.handleChange}
                 className="form-control" />
          <FieldFeedbacks for="phone">
            <FieldFeedback when="*" />
          </FieldFeedbacks>

          <input name="address" size="30" placeholder="Address"
                 required onChange={this.handleChange}
                 className="form-control" />
          <FieldFeedbacks for="address">
            <FieldFeedback when="*" />
          </FieldFeedbacks>
        </div>

        <div className="col-md-6">
          <textarea name="comments" cols="40" rows="20" placeholder="Message"
                    required minLength={5} maxLength={50}
                    onChange={this.handleChange}
                    className="form-control" />
          <FieldFeedbacks for="comments">
            <FieldFeedback when="*" />
          </FieldFeedbacks>
        </div>

        <div className="col-md-12">
          <button className="btn btn-lg btn-primary">Send Message</button>
        </div>
      </FormWithConstraints>
    );
  }
}

截图：

这是一个快速破解。如需正确的演示，请查看https://github.com/tkrotoff/react-form-with-constraints#examples

Answer 4

import React from 'react';
import {sendFormData} from '../services/';

class Signup extends React.Component{
  constructor(props){
    super(props);
     this.state = {
       isDisabled:true
     }                                                                                                 
     this.submitForm = this.submitForm.bind(this);
  }
  validateEmail(email){
   const pattern = /[a-zA-Z0-9]+[\.]?([a-zA-Z0-9]+)?[\@][a-z]{3,9}[\.][a-z]{2,5}/g;
   const result = pattern.test(email);
   if(result===true){
     this.setState({
       emailError:false,
       email:email
     })
   } else{
     this.setState({
       emailError:true
     })
   }
 }
 handleChange(e){
  const target = e.target;
  const value = target.type === 'checkbox' ? target.checked : target.value;
  const name = target.name;
  this.setState({
    [name]: value
  });
  if(e.target.name==='firstname'){
    if(e.target.value==='' || e.target.value===null ){
      this.setState({
        firstnameError:true
      })
    } else {
      this.setState({
        firstnameError:false,     
        firstName:e.target.value
      })
    }
  }
  if(e.target.name==='lastname'){
    if(e.target.value==='' || e.target.value===null){
      this.setState({
        lastnameError:true
      })
    } else {
      this.setState({
        lastnameError:false,
        lastName:e.target.value
      })
    }
  }
  if(e.target.name==='email'){
   this.validateEmail(e.target.value);
  }
  if(e.target.name==='password'){
    if(e.target.value==='' || e.target.value===null){
      this.setState({
        passwordError:true
      })
    } else {
      this.setState({
        passwordError:false,
        password:e.target.value
      })
    }
 }
 if(this.state.firstnameError===false && this.state.lastnameError===false && 
  this.state.emailError===false && this.state.passwordError===false){
    this.setState({
      isDisabled:false
    })
 }
}
submitForm(e){
  e.preventDefault();
  const data = {
   firstName: this.state.firstName,
   lastName: this.state.lastName,
   email: this.state.email,
   password: this.state.password
  }
  sendFormData(data).then(res=>{
    if(res.status===200){
      alert(res.data);
      this.props.history.push('/');
    }else{

    } 
  });
 }
render(){
return(
  <div className="container">
    <div className="card card-login mx-auto mt-5">
      <div className="card-header">Register here</div>
        <div className="card-body">
            <form id="signup-form">
              <div className="form-group">
                <div className="form-label-group">
                  <input type="text" id="firstname" name="firstname" className="form-control" placeholder="Enter firstname" onChange={(e)=>{this.handleChange(e)}} />
                  <label htmlFor="firstname">firstname</label>
                  {this.state.firstnameError ? <span style={{color: "red"}}>Please Enter some value</span> : ''} 
                </div>
              </div>
              <div className="form-group">
                <div className="form-label-group">
                  <input type="text" id="lastname" name="lastname" className="form-control" placeholder="Enter lastname" onChange={(e)=>{this.handleChange(e)}} />
                  <label htmlFor="lastname">lastname</label>
                  {this.state.lastnameError ? <span style={{color: "red"}}>Please Enter some value</span> : ''}
                </div>
              </div>
              <div className="form-group">
                <div className="form-label-group">
                  <input type="email" id="email" name="email" className="form-control" placeholder="Enter your email" onChange={(e)=>{this.handleChange(e)}} />
                  <label htmlFor="email">email</label>
                  {this.state.emailError ? <span style={{color: "red"}}>Please Enter valid email address</span> : ''}
                </div>
              </div>                
              <div className="form-group">
                <div className="form-label-group">
                  <input type="password" id="password" name="password" className="form-control" placeholder="Password" onChange={(e)=>{this.handleChange(e)}} />
                  <label htmlFor="password">Password</label>
                  {this.state.passwordError ? <span style={{color: "red"}}>Please enter some   value</span> : ''}
                </div>
              </div>                
              <button className="btn btn-primary btn-block" disabled={this.state.isDisabled} onClick={this.submitForm}>Signup</button>
            </form>
        </div>
      </div>
    </div>
  );
 }
}
export default Signup;

Answer 5

使用 React Hook，表单变得超级简单（React Hook 表单：https://github.com/bluebill1049/react-hook-form）

我已经重用了你的 html 标记。

import React from "react";
import useForm from 'react-hook-form';

function Test() {
  const { useForm, register } = useForm();
  const contactSubmit = data => {
    console.log(data);
  };

  return (
    <form name="contactform" onSubmit={contactSubmit}>
      <div className="col-md-6">
        <fieldset>
          <input name="name" type="text" size="30" placeholder="Name" ref={register} />
          <br />
          <input name="email" type="text" size="30" placeholder="Email" ref={register} />
          <br />
          <input name="phone" type="text" size="30" placeholder="Phone" ref={register} />
          <br />
          <input name="address" type="text" size="30" placeholder="Address" ref={register} />
          <br />
        </fieldset>
      </div>
      <div className="col-md-6">
        <fieldset>
          <textarea name="message" cols="40" rows="20" className="comments" placeholder="Message" ref={register} />
        </fieldset>
      </div>
      <div className="col-md-12">
        <fieldset>
          <button className="btn btn-lg pro" id="submit" value="Submit">
            Send Message
          </button>
        </fieldset>
      </div>
    </form>
  );
}

Answer 6

更简洁的方法是使用 joi-browser 包。在该状态下，您应该拥有包含表单中所有错误的错误对象。最初它应该设置为一个空对象。 创建架构；

import Joi from "joi-browser";
schema = {
    username: Joi.string()
      .required()
      .label("Username")
      .email(),
    password: Joi.string()
      .required()
      .label("Password")
      .min(8)
      .regex(/^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[^a-zA-Z0-9]).{8,1024}$/) //special/number/capital
   };

然后使用架构验证表单：

validate = () => {
    const options = { abortEarly: false };
    const result = Joi.validate(this.state.data, this.schema, options);
    console.log(data) // always analyze your data
    if (!result.error) return null; 
    const errors = {};
    for (let item of result.error.details) errors[item.path[0]] = item.message; //in details array, there are 2 properties,path and message.path is the name of the input, message is the error message for that input.
    return errors;
  };

在提交表单之前，请检查表单：

handleSubmit = e => {
    e.preventDefault();
    const errors = this.validate(); //will return an object
    console.log(errors);
    this.setState({ errors: errors || {} }); //in line 9 if we return {}, we dont need {} here
    if (errors) return;
    //so we dont need to call the server
    alert("success");
    //if there is no error call the server
    this.dosubmit();
  };

Answer 7

我们有很多选项来验证 react js 表单。也许 npm 包有一些自己的限制。根据您的需要，您可以选择正确的验证器包。我想推荐一些，如下所示。

• react-form-input-validation
• redux-form

如果有人知道比这更好的解决方案，请将其放在评论部分以供其他人参考。

Answer 8

可能会迟到回答 - 如果您不想大量修改当前代码并且仍然能够在整个项目中使用类似的验证代码，您也可以尝试这个 - https://github.com/vishalvisd/react-validator.

Answer 9

试试powerform-react。它基于powerform，这是一个超级便携的 Javascript 表单库。一旦学会，它可以在任何框架中使用。它甚至适用于原生 Javascript。

Checkout this simple form 使用powerform-react

还有一个complex example。

Answer 10

假设你知道 react useState Hook，如果你的表单很简单，你可以使用 state 变量来保存每个输入字段的值。然后在每个将更新状态变量的输入字段上添加onChange 处理函数。最后，您可以检查存储在状态变量中的值，以确保所有输入字段都有一些值。这是一个简单的例子。

import { useState } from "react";

export default function App() {
  const [name, setName] = useState("");
  const [email, setEmail] = useState("");
  const onChangeHandler = (fieldName, value)=>{
    if(fieldName === "name"){
      setName(value);
    }
    else if(fieldName==="email"){
      setEmail(value);
    }
  }
  const onSubmitHandler = (e)=>{
    e.preventDefault();
    if(name.trim()==="" || email.trim() ==""){
      alert("required both field");
    }
    else{
      alert(name+" " +email);
      setName("");
      setEmail("");
    }
  }
  return (
    <div className="App">
      <form onSubmit={(e)=>{onSubmitHandler(e)}}>
        <input type="text" value={name} onChange={(e)=>{ onChangeHandler("name",e.target.value)}} /> <br/>
         <input type="email"  value={email} onChange={(e)=>{ onChangeHandler("email",e.target.value)}} /> <br/>
         <input type="submit" value="Submit" />
        </form>
    </div>
  );
}

但是，如果您有一个复杂的表单，则很难将每个值保留在状态变量中，然后对每个字段进行验证。对于复杂的表单，建议使用Formik，它将为您完成所有工作，您可以使用Yup 验证包，Formik 也支持它，它允许您添加不仅仅是简单的验证。