import React from "react"
import { useForm } from "react-hook-form"

interface IFormInputs {
  name: string
  showAge: boolean
  age: number
}

function App() {
  const {
    register,
    watch,
    formState: { errors },
    handleSubmit,
  } = useForm<IFormInputs>()
  const watchShowAge = watch("showAge", false) // you can supply default value as second argument
  const watchAllFields = watch() // when pass nothing as argument, you are watching everything
  const watchFields = watch(["showAge", "age"]) // you can also target specific fields by their names

  // Callback version of watch.  It's your responsibility to unsubscribe when done.
  React.useEffect(() => {
    const subscription = watch((value, { name, type }) =>
      console.log(value, name, type)
    )
    return () => subscription.unsubscribe()
  }, [watch])

  const onSubmit = (data: IFormInputs) => console.log(data)

  return (
    <>
      <form onSubmit={handleSubmit(onSubmit)}>
        <input {...register("name", { required: true, maxLength: 50 })} />
        <input type="checkbox" {...register("showAge")} />
        {/* based on yes selection to display Age Input*/}
        {watchShowAge && (
          <input type="number" {...register("age", { min: 50 })} />
        )}
        <input type="submit" />
      </form>
    </>
  )
}

import React from "react"
import { useForm } from "react-hook-form"

function App() {
  const {
    register,
    watch,
    formState: { errors },
    handleSubmit,
  } = useForm()
  const watchShowAge = watch("showAge", false) // you can supply default value as second argument
  const watchAllFields = watch() // when pass nothing as argument, you are watching everything
  const watchFields = watch(["showAge", "number"]) // you can also target specific fields by their names

  // Callback version of watch.  It's your responsibility to unsubscribe when done.
  React.useEffect(() => {
    const subscription = watch((value, { name, type }) =>
      console.log(value, name, type)
    )
    return () => subscription.unsubscribe()
  }, [watch])

  const onSubmit = (data) => console.log(data)

  return (
    <>
      <form onSubmit={handleSubmit(onSubmit)}>
        <input type="checkbox" {...register("showAge")} />

        {/* based on yes selection to display Age Input*/}
        {watchShowAge && (
          <input type="number" {...register("age", { min: 50 })} />
        )}

        <input type="submit" />
      </form>
    </>
  )
}

import * as React from "react"
import { useForm, useFieldArray } from "react-hook-form"

type FormValues = {
  test: {
    firstName: string
    lastName: string
  }[]
}

function App() {
  const { register, control, handleSubmit, watch } = useForm<FormValues>()
  const { fields, remove, append } = useFieldArray({
    name: "test",
    control,
  })
  const onSubmit = (data: FormValues) => console.log(data)

  console.log(watch("test"))

  return (
    <form onSubmit={handleSubmit(onSubmit)}>
      {fields.map((field, index) => {
        return (
          <div key={field.id}>
            <input
              defaultValue={field.firstName}
              {...register(`test.${index}.firstName`)}
            />
            <input
              defaultValue={field.lastName}
              {...register(`test.${index}.lastName`)}
            />
            <button type="button" onClick={() => remove(index)}>
              Remove
            </button>
          </div>
        )
      })}
      <button
        type="button"
        onClick={() =>
          append({
            firstName: "bill" + renderCount,
            lastName: "luo" + renderCount,
          })
        }
      >
        Append
      </button>
    </form>
  )
}

import * as React from "react"
import { useForm, useFieldArray } from "react-hook-form"

function App() {
  const { register, control, handleSubmit, watch } = useForm()
  const { fields, remove, append } = useFieldArray({
    name: "test",
    control,
  })
  const onSubmit = (data) => console.log(data)

  console.log(watch("test"))

  return (
    <form onSubmit={handleSubmit(onSubmit)}>
      {fields.map((field, index) => {
        return (
          <div key={field.id}>
            <input
              defaultValue={field.firstName}
              {...register(`test.${index}.firstName`)}
            />
            <input
              defaultValue={field.lastName}
              {...register(`test.${index}.lastName`)}
            />
            <button type="button" onClick={() => remove(index)}>
              Remove
            </button>
          </div>
        )
      })}
      <button
        type="button"
        onClick={() =>
          append({
            firstName: "bill" + renderCount,
            lastName: "luo" + renderCount,
          })
        }
      >
        Append
      </button>
    </form>
  )
}