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trigger

Trigger validation across the form

trigger: (name?: string | string[]) => void

Manually triggers form or input validation. This method is also useful when you have dependant validation (input validation depends on another input's value).

Props

TypeDescriptionExample
undefinedTriggers validation on all fields.trigger()
stringTriggers validation on a specific field value by nametrigger("yourDetails.firstName")
string[]Triggers validation on multiple fields by name.trigger(["yourDetails.lastName"])
CodeSandbox 
import React from "react";
import { useForm } from "react-hook-form";

export default function App() {
  const { register, trigger, errors } = useForm();

  return (
    <form>
      <input {...register("firstName", { required: true })} />
      <input {...register("lastName", { required: true })} />
      <button type="button" onClick={() => { trigger("lastName"); }}>Trigger</button>
      <button type="button" onClick={() => { trigger(["firstName", "lastName"]); }}>Trigger Multiple</button>
      <button type="button" onClick={() => { trigger(); }}>Trigger All</button>
    </form>
  );
}import React from "react";
import { useForm } from "react-hook-form";

type FormInputs = {
  firstName: string
  lastName: string
}

export default function App() {
  const { register, trigger, errors } = useForm<FormInputs>();

  return (
    <form>
      <input {...register("firstName", { required: true })} />
      <input {...register("lastName", { required: true })} />
      <button type="button" onClick={() => { trigger("lastName"); }}>Trigger</button>
      <button type="button" onClick={() => { trigger(["firstName", "lastName"]); }}>Trigger Multiple</button>
      <button type="button" onClick={() => { trigger(); }}>Trigger All</button>
    </form>
  );
}
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