Create FormData

createFormData

Converts JavaScript objects into FormData with extensive configuration options for handling nested structures, files, and case transformations.

Function Signature

function createFormData<T extends GenericObject>(
  data: T,
  configs?: FormDataConfigs<T>
): FormData

Parameters

Returns

• FormData: A standard FormData instance containing the mapped inputs.

Example Usage

Behavior Details

Nested Objects

• By default, nested objects are JSON-stringified (JSON.stringify) which is standard for modern API submissions.
• Pass keys to dotNotateNested to flatten them recursively into dot-notated parameters (e.g. user.address.zip).

File Uploads

• Automatically handles standard File, Blob, FileList, and file-upload formats from common UI Component Libraries (such as Ant Design).

Case & Whitespace Control

• Trims all string values when trimStrings is true.
• Converts specific key paths or values to lowercase using lowerCaseKeys and lowerCaseValues.

Aliases

This function can also be imported under the following name:

Types

FormDataConfigs

interface FormDataConfigs<T> {
  ignoreKeys?: DotNotationKey<T>[];
  requiredKeys?: '*' | DotNotationKey<T>[];
  lowerCaseKeys?: '*' | DotNotationKey<T>[];
  lowerCaseValues?: '*' | NestedKeyString<T>[];
  dotNotateNested?: '*' | KeyForObject<T>[];
  stringifyNested?: '*' | KeyForObject<T>[];
  breakArray?: '*' | KeyForArray<T>[];
  trimStrings?: boolean;
}