React Js Form Validation and Conditional Select Example

Html:

<div id="container" class="ui two column centered grid">
  <div class="column">
    <h1 class="ui dividing header">React Form</h1>
    <div id="content"></div>  
  </div>
    
</div>

<h1 class="ui dividing header">React Form</h1>

</div>

Css:

#container {
  margin-top: 6em;
}

#container {

margin-top: 6em;

}

Js:

const Dropdown = semanticUIReact.Dropdown;
const SemanticForm = semanticUIReact.Form;
const SemanticButton = semanticUIReact.Button;

const COURSES = {core: ["javascripting","git-it","Scope Chains & Closures","Elementary Electron","learnyounode","How to npm","stream-adventure","how-to-markdown"], electives: [ "Functional Javascript", "Level Me Up Scotty!", "ExpressWorks", "Make Me Hapi", "Promise It Won't Hurt", "Async You", "NodeBot Workshop", "Going Native", "Planet Proto", "WebGL Workshop", "ESNext Generation", "Test Anything", "Tower of babel", "learnyoumongo", "regex-adventure", "learn-sass", "Pattern Lab Workshop", "learnyoubash", "Currying in JavaScript", "Shader School", "Bytewiser", "Bug Clinic", "Browserify Adventure", "Intro to WebGL", "Count to 6", "Kick off Koa", "LololoDash", "learnyoucouchdb", "learnuv", "Learn Generators", "learnyoureact", "perfschool", "Web Audio School", "torrential", "Thinking in React", "Post-mortem debugging", "Seneca in practice", "LESS is more" ],};

class Form extends React.Component {
  state = {
    people: [{name:'potato', email:'potato@person.com', department:'core', course:'javascripting'}],
    fields: {
      name: '',
      email: '',
      department: null,
      course: null,
    },
    fieldErrors: {},
  };

  onInputChange = ({name, value, error}) => {
    const fields = this.state.fields;
    const fieldErrors = this.state.fieldErrors;
    
    fields[name] = value;
    fieldErrors[name] = error;
    
    this.setState({ fields, fieldErrors });
  };
  
  onFormSubmit = evt => {
    const people = [ ...this.state.people ];
    const person = this.state.fields;
    evt.preventDefault(); // prevents page from reloading on submit
    
    if (this.validate()) return;
    
    this.setState({
      people: people.concat(person),
      fields: {
        name: '',
        email: '',
      },
    });  
  };

  validate = () => {
    // Checks data is valid at form level
    // To pass this check neither field can be empty and they must pass field level validation
    const person = this.state.fields;    
    const fieldErrors = this.state.fieldErrors;
    const errMessages = Object.keys(fieldErrors).filter(k => fieldErrors[k]);
    
    if (!person.name) return true;
    if (!person.email) return true;
    if (!person.course) return true;
    if (!person.department) return true;
    if (errMessages.length) return true;
    
    return false;
  };
  
  render() {
    return (
      <div>
        <h2 className="ui header">Sign Up Sheet</h2>
        <SemanticForm onSubmit={this.onFormSubmit}>
          <Field 
            name="name" 
            onChange={this.onInputChange}
            placeholder="Name" 
            value={this.state.fields.name} 
            validate={val => val ? false : 'Name Required'} />
          <Field 
            name="email" 
            onChange={this.onInputChange} 
            placeholder="Email" 
            value={this.state.fields.email} 
            validate={val => validator.isEmail(val) ? false : 'Invalid Email'} />
          <CourseSelect 
            onChange={this.onInputChange}
            department={this.state.fields.department}
            course={this.state.fields.course} />
          <br />
          <SemanticButton type="submit" disabled={this.validate()}>Submit Form</SemanticButton>
        </SemanticForm>
        <hr />
        <h3>People</h3>
        <div className="ui list">
          {this.state.people.map((person,i) => 
            (<li className="item" key={'person-'+i}><i className="user icon"></i>{person.name} - {person.email} - {person.department} - {person.course}</li>)
          )}
        </div>
      </div>
    );
  }
}

class Field extends React.Component {
  static propTypes = {
    placeholder: PropTypes.string,
    name: PropTypes.string.isRequired,
    value: PropTypes.string,
    validate: PropTypes.func,
    onChange: PropTypes.func.isRequired,
  };

  state = {
    value: this.props.value,
    error: false,
  };

  componentWillReceiveProps(update) {
    // This is needed because the value prop is set to state (not just passed through) 
    // The state won't automatically update from the prop after it has been initially set
    this.setState({ value: update.value });
  };

  onChange = evt => {
    const name = this.props.name;
    const value = evt.target.value;
    const error = this.props.validate ? this.props.validate(value) : false;
    
    this.setState({value, error});
    
    this.props.onChange({name, value, error});
  };

  render() {
    return (
      <div className="field">
        <label>{this.props.placeholder}</label>
        <input 
          placeholder={this.props.placeholder} 
          value={this.state.value} 
          onChange={this.onChange} />
        {this.state.error && <div className="ui visible warning message">{this.state.error}</div>}
      </div>
    );
  };
}

class CourseSelect extends React.Component {
  static propTypes = {
    department: PropTypes.string,
    course: PropTypes.string,
    onChange: PropTypes.func.isRequired,
  };
  
  state = {
    department: null,
    course: null,
    courses: [],
    _loading: false,
  };

  componentWillReceiveProps(update) {
    this.setState({
      department: update.department,
      course: update.course, 
    });
  }

  onDepartmentSelect = (evt, data) => {
    const department = data.value;
    const course = null;
    const courses = COURSES[department] || [];
    this.setState({ department, course, courses });
    this.props.onChange({name: 'department', value: department});
    this.props.onChange({name: 'course', value: course});
  };
  
  onCourseSelect = (evt, data) => {
    const course = data.value;
    this.setState({ course });
    this.props.onChange({name: 'course', value: course});
  }

  renderDepartmentSelect = () => {
        
    const departmentOptions = [
      {text: "", value: ""},
      {text: "NodeSchool: Core", value: "core"},
      {text: "NodeSchool: Electives", value: "electives"},
    ]
    return (
      <div className="field">
        <label>Department</label>
        <Dropdown 
          placeholder="Which department?" 
          fluid={true} 
          selection={true} 
          options={departmentOptions} 
          value={this.state.department || ''} 
          onChange={this.onDepartmentSelect} />
      </div>
    );
  };

  renderCourseSelect = () => {
    const courseOptions = [{text:'', value: ''},]
      .concat(this.state.courses.map(courseOption => {
        return {value: courseOption, text: courseOption,};
      }));
    return (
      <div className="field" hidden={!this.state.courses.length}>
        <label>Course</label>
        <Dropdown 
          placeholder="Which course?" 
          fluid={true} 
          selection={true} 
          options={courseOptions} 
          value={this.state.course || ''} 
          onChange={this.onCourseSelect} />
      </div>
    );
    // return (<div></div>);
  };

  render() {
    return (
      <div>
        {this.renderDepartmentSelect()}
        {this.renderCourseSelect()}
      </div>
    );
  }
}

ReactDOM.render(
  <Form />,
  document.getElementById('content')
);

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const Dropdown = semanticUIReact.Dropdown;

const SemanticForm = semanticUIReact.Form;

const SemanticButton = semanticUIReact.Button;

const COURSES = {core: ["javascripting","git-it","Scope Chains & Closures","Elementary Electron","learnyounode","How to npm","stream-adventure","how-to-markdown"], electives: [ "Functional Javascript", "Level Me Up Scotty!", "ExpressWorks", "Make Me Hapi", "Promise It Won't Hurt", "Async You", "NodeBot Workshop", "Going Native", "Planet Proto", "WebGL Workshop", "ESNext Generation", "Test Anything", "Tower of babel", "learnyoumongo", "regex-adventure", "learn-sass", "Pattern Lab Workshop", "learnyoubash", "Currying in JavaScript", "Shader School", "Bytewiser", "Bug Clinic", "Browserify Adventure", "Intro to WebGL", "Count to 6", "Kick off Koa", "LololoDash", "learnyoucouchdb", "learnuv", "Learn Generators", "learnyoureact", "perfschool", "Web Audio School", "torrential", "Thinking in React", "Post-mortem debugging", "Seneca in practice", "LESS is more" ],};

class Form extends React.Component {

state = {

people: [{name:'potato', email:'potato@person.com', department:'core', course:'javascripting'}],

fields: {

email: '',

department: null,

course: null,

fieldErrors: {},

};

onInputChange = ({name, value, error}) => {

const fields = this.state.fields;

const fieldErrors = this.state.fieldErrors;

fields[name] = value;

fieldErrors[name] = error;

this.setState({ fields, fieldErrors });

};

onFormSubmit = evt => {

const people = [ ...this.state.people ];

const person = this.state.fields;

evt.preventDefault(); // prevents page from reloading on submit

if (this.validate()) return;

this.setState({

people: people.concat(person),

fields: {

email: '',

});

};

validate = () => {

// Checks data is valid at form level

// To pass this check neither field can be empty and they must pass field level validation

const person = this.state.fields;

const fieldErrors = this.state.fieldErrors;

const errMessages = Object.keys(fieldErrors).filter(k => fieldErrors[k]);

if (!person.name) return true;

if (!person.email) return true;

if (!person.course) return true;

if (!person.department) return true;

if (errMessages.length) return true;

return false;

};

render() {

return (

<div>

<h2 className="ui header">Sign Up Sheet</h2>

<Field

name="name"

onChange={this.onInputChange}

placeholder="Name"

value={this.state.fields.name}

validate={val => val ? false : 'Name Required'} />

<Field

name="email"

onChange={this.onInputChange}

placeholder="Email"

value={this.state.fields.email}

validate={val => validator.isEmail(val) ? false : 'Invalid Email'} />

<CourseSelect

onChange={this.onInputChange}

department={this.state.fields.department}

course={this.state.fields.course} />

<br />

<SemanticButton type="submit" disabled={this.validate()}>Submit Form</SemanticButton>

</SemanticForm>

<hr />

<h3>People</h3>

{this.state.people.map((person,i) =>

(<li className="item" key={'person-'+i}><i className="user icon"></i>{person.name} - {person.email} - {person.department} - {person.course}</li>)

)}

</div>

);

}

class Field extends React.Component {

static propTypes = {

placeholder: PropTypes.string,

value: PropTypes.string,

validate: PropTypes.func,

onChange: PropTypes.func.isRequired,

};

state = {

value: this.props.value,

error: false,

};

componentWillReceiveProps(update) {

// This is needed because the value prop is set to state (not just passed through)

// The state won't automatically update from the prop after it has been initially set

this.setState({ value: update.value });

};

onChange = evt => {

const name = this.props.name;

const value = evt.target.value;

const error = this.props.validate ? this.props.validate(value) : false;

this.setState({value, error});

this.props.onChange({name, value, error});

};

render() {

return (

<label>{this.props.placeholder}</label>

<input

placeholder={this.props.placeholder}

value={this.state.value}

onChange={this.onChange} />

{this.state.error && <div className="ui visible warning message">{this.state.error}</div>}

</div>

);

};

}

class CourseSelect extends React.Component {

static propTypes = {

department: PropTypes.string,

course: PropTypes.string,

onChange: PropTypes.func.isRequired,

};

state = {

department: null,

course: null,

courses: [],

_loading: false,

};

componentWillReceiveProps(update) {

this.setState({

department: update.department,

course: update.course,

});

}

onDepartmentSelect = (evt, data) => {

const department = data.value;

const course = null;

const courses = COURSES[department] || [];

this.setState({ department, course, courses });

this.props.onChange({name: 'department', value: department});

this.props.onChange({name: 'course', value: course});

};

onCourseSelect = (evt, data) => {

const course = data.value;

this.setState({ course });

this.props.onChange({name: 'course', value: course});

}

renderDepartmentSelect = () => {

const departmentOptions = [

{text: "", value: ""},

{text: "NodeSchool: Core", value: "core"},

{text: "NodeSchool: Electives", value: "electives"},

]

return (

<label>Department</label>

<Dropdown

placeholder="Which department?"

fluid={true}

selection={true}

options={departmentOptions}

value={this.state.department || ''}

onChange={this.onDepartmentSelect} />

</div>

);

};

renderCourseSelect = () => {

const courseOptions = [{text:'', value: ''},]

.concat(this.state.courses.map(courseOption => {

return {value: courseOption, text: courseOption,};

}));

return (

<label>Course</label>

<Dropdown

placeholder="Which course?"

fluid={true}

selection={true}

options={courseOptions}

value={this.state.course || ''}

onChange={this.onCourseSelect} />

</div>

);

// return (<div></div>);

};

render() {

return (

<div>

{this.renderDepartmentSelect()}

{this.renderCourseSelect()}

</div>

);

}

ReactDOM.render(

<Form />,

document.getElementById('content')

);

Source Code: https://codepen.io/parc6502/pen/Koajzd

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