form

Low-level and simple react components to handle common form logic.

npm install --save form-logic

• Why
• Example
• API

Why

Forms are always made up of the same logic :

• Enable submit when certains values are filled
• Disable submit and/or inputs when a request is in flight, or there is an error

But the exacts prerequisites are always custom to each form.
This library exposes 2 components : <Form/> and <FormBehave/>.

<Form/> exposes a context made of requests, values and errors.
<FormBehave/> allows to react and interact with this context.

Example

Here is a simple form implementing most basics functionnalities :

• The header displays itself differently if the user has filled its name.
• Register button is disabled until inputs are filled
• Register button and the inputs are disabled when the request is in flight

<Form>
  <FormBehave render={({ values }) => (
    <h1>
      {values.name
        ? `Hello, ${values.name} !`
        : 'Who are you ?'}
    </h1>
  )}/>

  <div>
    <FormBehave render={({ requests, values }, { setValue }) => (
      <Input
        type="text"
        placeholder="Name"
        value={values.name || ''}
        onChange={(e) => setValue('name', e.target.value)}
        disabled={!!requests.register}
      />
    )}/>

    <FormBehave render={({ requests, values }, { setValue }) => (
      <Input
        type="text"
        placeholder="Last name"
        value={values.lastName || ''}
        onChange={(e) => setValue('lastName', e.target.value)}
        disabled={!!requests.register}
      />
    )}/>
  </div>

  <FormBehave render={({ requests, values }, { registerRequest }) => (
    <Button
      onClick={() => registerRequest('register', this.register())}
      disabled={!values.name || !values.lastName || requests.register}
    >
      {!!requests.register
        ? 'Registering...'
        : 'Register !'}
    </Button>
  )}/>
</Form>

API

• <Form/> Provides context for any <FormBehave/> children.
• <FormBehave render={fn} />
• prop render (FormData, FormContext) => ?React$Element

type FormData = {
  requests: {
    [key: string]: Promise<any>,
  },
  values: {
    [key: string]: any,
  },
  errors: {
    [key: string]: string,
  },
};

type FormContext = {
  registerRequest: (string, Promise<any>) => void,
  setValue: (string, any) => void,
  setError: (string, any) => void,
};