extract-files

What is extract-files?

The extract-files package is designed to extract files from a JavaScript object tree so they can be uploaded via a multipart request. It is commonly used in applications that need to handle file uploads, especially in the context of GraphQL operations.

What are extract-files's main functionalities?

Extract files from an object

This feature allows you to extract files from an object, which is useful when preparing files for upload. The `extractFiles` function takes an object and a path to traverse within the object to find files. It returns an object with the extracted files and a clone of the original object with files replaced by null.

{"operation": "const { extractFiles } = require('extract-files');\nconst file = new File(['content'], 'file.txt', { type: 'text/plain' });\nconst operation = { variables: { file } };\nconst { files, clone } = extractFiles(operation, 'variables');"}

Support for FileList and Map objects

The package can handle `FileList` objects, which are typically obtained from file input elements, and `Map` objects. It can extract files from these complex structures, making it versatile for various file upload scenarios.

{"operation": "const { extractFiles } = require('extract-files');\nconst fileList = document.querySelector('input[type=file]').files;\nconst operation = { variables: { files: fileList } };\nconst { files, clone } = extractFiles(operation, 'variables');"}

Other packages similar to extract-files

form-data

The form-data package allows you to create `multipart/form-data` streams to submit files and values via HTTP. It can be used to simulate a form submission with file uploads, similar to extract-files, but it is more focused on constructing the form data itself rather than extracting files from an existing object structure.

busboy

Busboy is a Node.js module for parsing incoming HTML form data, including file uploads. It differs from extract-files in that it is used on the server side to process file uploads, whereas extract-files is typically used on the client side to prepare files for upload.

multer

Multer is a Node.js middleware for handling `multipart/form-data`, primarily used for uploading files. It is similar to busboy but is designed to be used with Express applications. Unlike extract-files, multer is not about extracting files from an object but rather about handling file uploads on the server side.

README

extract-files

A function to recursively extract files and their object paths within a value, replacing them with null in a deep clone without mutating the original value. FileList instances are treated as File instance arrays. Files are typically File and Blob instances.

Used by GraphQL multipart request spec client implementations such as graphql-react and apollo-upload-client.

Installation

For Node.js, to install extract-files with npm, run:

npm install extract-files

For Deno and browsers, an example import map:

{
  "imports": {
    "extract-files/": "https://unpkg.com/extract-files@13.0.0/",
    "is-plain-obj": "https://unpkg.com/is-plain-obj@4.1.0/index.js",
    "is-plain-obj/": "https://unpkg.com/is-plain-obj@4.1.0/"
  }
}

See the function extractFiles to get started.

Requirements

Supported runtime environments:

• Node.js versions ^14.17.0 || ^16.0.0 || >= 18.0.0.
• Deno, importing from a CDN that might require an import map for dependencies.
• Browsers matching the Browserslist query > 0.5%, not OperaMini all, not dead.

Non Deno projects must configure TypeScript to use types from the ECMAScript modules that have a // @ts-check comment:

• compilerOptions.allowJs should be true.
• compilerOptions.maxNodeModuleJsDepth should be reasonably large, e.g. 10.
• compilerOptions.module should be "node16" or "nodenext".

Exports

The npm package extract-files features optimal JavaScript module design. It doesn’t have a main index module, so use deep imports from the ECMAScript modules that are exported via the package.json field exports:

• extractFiles.mjs
• isExtractableFile.mjs