Parse FormData

Converts FormData or query strings into structured JavaScript objects with optional primitive parsing.

parseFormData

Converts FormData or query strings into structured JavaScript objects, with optional primitive value parsing.

Function Signature

function parseFormData<D, P>(data: D, parsePrimitives?: P): ParsedFormData<D, P>

Parameters

Parameter	Type	Description	Default
`data`	`FormData \| string`	Input data to parse.	—
`parsePrimitives`	`boolean` (optional)	Whether to convert string values into actual types (booleans, numbers, arrays, objects).	`true`

Returns

ParsedFormData<T>: A structured object containing the parsed inputs.

Example Usage

playground.ts

Behavior Details

Array Handling: Duplicate keys or multi-value entries automatically get parsed into arrays.
File Object Preservation: File objects are preserved as-is when parsing FormData, maintaining original MIME types and binary content.
Primitive Parsing: When parsePrimitives is true, it uses parseObjectValues internally to parse string values.

Type Definitions

type TypeOrArray<T> = T | Array<T>;

type NormalPrimitive = string | number | boolean | null | undefined;

type ParsedFormData<T extends FormData | string, P extends boolean> = T extends string
	? Record<string, P extends true ? TypeOrArray<NormalPrimitive> : TypeOrArray<string>>
	: Record<
			string,
			P extends true ? TypeOrArray<NormalPrimitive | File> : TypeOrArray<string | File>
		>;