form-data-encoder

Encode FormData content into the multipart/form-data format

Requirements

• browsers or Deno

Usage

import { FormDataEncoder } from "https://code4fukui.github.io/form-data-encoder/FormDataEncoder.js";

const form = new FormData();
form.set("a", 15);
form.set("b", "test");
form.set("file", new Blob([new Uint8Array([1, 2, 3])]), "a.txt");

const { headers, body } = await FormDataEncoder.encode(form);
console.log(headers, new TextDecoder().decode(body));

Build

TypeScript → JavaScript

npm i
npm run build

API

class FormDataEncoder

constructor(form[, boundary, options]) -> {FormDataEncoder}

• {FormDataLike} form - FormData object to encode. This object must be a spec-compatible FormData implementation.
• {string} [boundary] - An optional boundary string that will be used by the encoder. If there's no boundary string is present, FormDataEncoder will generate it automatically.
• {object} [options] - FormDataEncoder options.
• {boolean} [options.enableAdditionalHeaders = false] - When enabled, the encoder will emit additional per part headers, such as Content-Length. Please note that the web clients do not include these, so when enabled this option might cause an error if multipart/form-data does not consider additional headers.

Creates a multipart/form-data encoder.

Instance properties

boundary -> {string}

Returns boundary string.

contentType -> {string}

Returns Content-Type header.

contentLength -> {string}

Return Content-Length header.

headers -> {object}

Returns headers object with Content-Type and Content-Length header.

Instance methods

values() -> {Generator<Uint8Array | FileLike, void, undefined>}

Creates an iterator allowing to go through form-data parts (with metadata). This method will not read the files.

encode() -> {AsyncGenerator<Uint8Array, void, undefined>}

Creates an async iterator allowing to perform the encoding by portions. This method will also read files.

[Symbol.iterator]() -> {Generator<Uint8Array | FileLike, void, undefined>}

An alias for Encoder#values() method.

[Symbol.asyncIterator]() -> {AsyncGenerator<Uint8Array, void, undefined>}

An alias for Encoder#encode() method.

isFile(value) -> {boolean}

Check if a value is File-ish object.

• {unknown} value - a value to test

isFormData(value) -> {boolean}

Check if a value is FormData-ish object.

• {unknown} value - a value to test