trigger: (name?: string | string[]) => Promise<boolean>

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

Name	Type	Description	Example
name	`undefined`	Triggers validation on all fields.	`trigger()`
	`string`	Triggers validation on a specific field value by name	`trigger("yourDetails.firstName")`
	`string[]`	Triggers validation on multiple fields by name.	`trigger(["yourDetails.lastName"])`
shouldFocus	`boolean`	Should focus the input during setting an error. This only works when the input's reference is registered, it will not work for custom register as well.	`trigger('name', { shouldFocus: true })`

Rules

Isolate render optimisation only applicable for targeting a single field name with string as payload, when supplied with array and undefined to trigger will re-render the entire formState.

Examples

CodeSandbox

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

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

  return (
    <form>
      <input {...register("firstName", { required: true })} />
      <input {...register("lastName", { required: true })} />
      <button
        type="button"
        onClick={async () => {
          const result = await trigger("lastName");
          // const result = await trigger("lastName", { shouldFocus: true }); allowed to focus input
        }}
      >
        Trigger
      </button>
      <button
        type="button"
        onClick={async () => {
          const result = await 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";

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

  return (
    <form>
      <input {...register("firstName", { required: true })} />
      <input {...register("lastName", { required: true })} />
      <button
        type="button"
        onClick={async () => {
          const result = await trigger("lastName");
          // const result = await trigger("lastName", { shouldFocus: true }); allowed to focus input
        }}
      >
        Trigger
      </button>
      <button
        type="button"
        onClick={async () => {
          const result = await trigger(["firstName", "lastName"]);
        }}
      >
        Trigger Multiple
      </button>
      <button
        type="button"
        onClick={() => {
          trigger();
        }}
      >
        Trigger All
      </button>
    </form>
  );
}

Video

The following video explain trigger API in detail.

Thank you for your support

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