Remix Params Helper

This package makes it simple to use Zod with standard URLSearchParams and FormData which are typically used in Remix apps.

🚨 Breaking Change v0.3.0

Helper no longer requires explicit types on helper. Thanks @zolrath. This will definitely cut down on the boilerplate.

🚧 Work in progress

This package is still work in progress. I'll be refining the API and fixing the TypeScript types.

🛠 Installation

npm install remix-params-helper zod

Zod is a peer dependency

📦 Zod

Zod is used to validate untyped data and either return a valid object or a list of errors encounted.

To use the helper, first define your Zod schema. It also supports nested objects and arrays.

const ParamsSchema = z.object({
  a: z.number(),
  b: z.string(),
  c: z.boolean(),
  d: z.string().optional(),
  e: z.array(z.number()),
})

📝 API Reference

`getParams(params, schema)`

This function is used to parse and validate data from URLSearchParams, FormData, or Remix params object.

It returns an object that has success property. If result.success is true then result.data will be a valid object of type T, inferred from your Zod schema.

Otherwise, result.errors will be an object with keys for each property that failed validation. The key value will be the validation error message.

NOTE: Error messages will now return the message from directly Zod. You can customize the error message in your Zod schema Zod Custom Error Messages

If the validation returns multiple errors for the same key, it will return an array, otherwise it will be a string.

errors[key] = 'message'
errors[key] = ['message 1', 'message 2']

Unlike Object.fromEntries(), this function also supports multi-value keys and will convert them to an array. So e=1&e=2&e=3 will convert it to e: [1,2,3]

const url = new URL(request.url)
const result = getParams(url.searchParams, ParamsSchema)
if (!result.success) {
  throw new Response(result.errors, { status: 400 })
}
// these variables will be typed and valid
const { a, b, c, d, e } = result.data

`getSearchParams(request, schema)`

This helper function is used to parse and validate URLSearchParams data from the Request found in the Remix action/loader, it returns the same result values as getParams.

const result = getSearchParams(request, ParamsSchema)
if (!result.success) {
  return json(result.errors, { status: 400 })
}
// these variable will be typed and valid
const { a, b, c, d, e } = result.data

`getFormData(request, schema)`

This helper function is used to parse and validate FormData data from the Request found in the Remix action/loader, it returns the same result values as getParams.

const result = await getFormData(request, ParamsSchema)
if (!result.success) {
  return json(result.errors, { status: 400 })
}
// these variables will be typed and valid
const { a, b, c, d, e } = result.data

✨ New in v0.4.2 Added `*OrFail()` versions of the helpers

The functions getParamsOrFail(), getFormDataOrFail(), getSearchParamsOrFail() will throw an Error when parsing fails. Since the helper can only return a valid result, the return value is always the data.

// returns valid data that can be destructured or Error is thrown
const { a, b, c, d, e } = await getFormDataOrFail(request, ParamsSchema)

NOTE: Although we provide these helpers, it is recommended that you return errors instead of throwing. Form validation is typically an expected error. Throwing Error should be reserved for unexpected errors.

✨ New in v0.4.0 Support for nested objects and arrays

Input names should be dot-separated (e.g, address.street). Array names can include the square brackets (e.g., favoriteFoods[]). These are optional. The helper will correctly determine if the value is an array.

describe('test nested objects and arrays', () => {
  it('should validate nested object', () => {
    const mySchema = z.object({
      name: z.string(),
      address: z.object({
        street: z.string(),
        city: z.string(),
        state: z.string(),
        zip: z.string(),
      }),
    })
    const formData = new FormData()
    formData.set('name', 'abcdef')
    formData.set('address.street', '123 Main St')
    formData.set('address.city', 'Anytown')
    formData.set('address.state', 'US')
    formData.set('address.zip', '12345')
    const result = getParams(formData, mySchema)
    expect(result.success).toBe(true)
    expect(result.data.address.street).toBe('123 Main St')
  })
  it('should validate arrays with [] syntax', () => {
    const mySchema = z.object({
      name: z.string(),
      favoriteFoods: z.array(z.string()),
    })
    const formData = new FormData()
    formData.set('name', 'abcdef')
    formData.append('favoriteFoods[]', 'Pizza')
    formData.append('favoriteFoods[]', 'Tacos')
    formData.append('favoriteFoods[]', 'Hamburgers')
    formData.append('favoriteFoods[]', 'Sushi')
    const result = getParams(formData, mySchema)
    expect(result.success).toBe(true)
    expect(result.data.favoriteFoods?.length).toBe(4)
  })
})

`useFormInputProps(schema)`

This helper allows you to set the props on your form <input/> based on your Zod schema.

The function returns another function that you use to spread the properties on your input. It currently sets the following props based on the key value you specify. If you need to override any of the props, just add it after you spread.

name
type: text, number, checkbox, date, email, url
required: not .optional()
min/max: number
minlength/maxlength: text
pattern: regex

If the key doesn't exist in the schema, it will throw an error. This way if you rename any properties, it will force you to use the correct key.

This currently uses the native browser validation like required. I plan on adding enhanced client-side validation that will utilize the same Zod schema.

function Component() {
  const inputProps = useFormInputProps(schema)

  return (
    <Form>
      <input ...{inputProps('a')} />
      <input ...{inputProps('b')} />
      <input ...{inputProps('c')} />
      {/* This will throw an error since 'x' is not in schema*/}
      <input ...{inputProps('x')} />
    </Form>
  )
}