Form State Management in React

I'm Kuldeep
   

   /@bietkul

What does React Offer?

Controlled Components
Where form data is handled by React Component

Uncontrolled Components

Where form data is handled by the DOM

What's the need of a form library?

  • Form Validation and error Handling
     
  • Handling form submissions
     
  • Code Complexity
     
  • Interaction between input elements
     
  • Performance

Why not redux forms?

 

"Use React for ephemeral state that doesn’t matter to the app globally and doesn’t mutate in complex ways. For example, a toggle in some UI element, a form input state. Use Redux for state that matters globally or is mutated in complex ways. For example, cached users, or a post draft."

                                                                         - Dan Abramov

Problems with the current libraries

  • Dependency issues
     
  • BoilerPlate
     
  • UI Independent
     
  • Nested Forms
     
  • Dynamic Changes
     
  • Update Options
     

React Reactive Forms

  • Zero dependency
     
  • UI Independent
     
  • Nested Forms
     
  • Dynamic Changes
     
  • Listeners
     
  • Update Options

How it works ?

Create a control

                                            
        


                    this.myForm = FormBuilder.group({
                    
                        username: ["", Validators.required],
                    
                        password: ["", Validators.required]
                    
                    },
                    {
                        
                        updateOn: "submit"
                    
                    })
        

    <FieldGroup
        control={this.myForm}
        render={() => (

        <form>

            <FieldControl
                name="username"
                render={({ handler, hasError }) => (
                    <div>
                        <input type="text" {...handler()}/>
                        <span>
                            {hasError("required") && "Please enter username"}
                        </span>
                     </div>
                )}
            />

            <FieldControl
                name="password"
                render={({ handler, hasError }) => (
                    <div>
                        <input type="password" {...handler()}/>
                        <span>
                            {hasError("required") && "Please enter password"}
                        </span>
                     </div>
                )}
            />

         </form>
       )}
    />

Use the control in React component

        

    <FieldGroup
        render={() => (

        <form>

            <FieldControl
                name="username"
                render={({ handler, hasError }) => (
                    <div>
                        <input type="text" {...handler()}/>
                        <span>
                            {hasError("required") && "Please enter username"}
                        </span>
                     </div>
                )}
            />

            <FieldControl
                name="password"
                render={({ handler, hasError }) => (
                    <div>
                        <input type="password" {...handler()}/>
                        <span>
                            {hasError("required") && "Please enter password"}
                        </span>
                     </div>
                )}
            />

         </form>
       )}
    />

Use Dynamic Controls

  
    
        componentDidMount() {

            this.myForm.get('username').valueChanges.subscribe((value) => {

              const passwordControl = this.myForm.get('password')

              if(value) {

                passwordControl.disable()
                
                // this.myForm.disable()
                
                // passwordControl.setValue("demo")

                // passwordControl.setValidators(Validators.required)

                // passwordControl.setErrors({ "isExist": true })

              }

            })
         }

Subscribers

React JS Bangalore@31st Form State Management in React

By kuldep saxena

React JS Bangalore@31st Form State Management in React

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