bs-fetch

library0.6.2jsnpmunverified

Low-level OCaml/ReasonML bindings to the Fetch API for BuckleScript (Belt/bs-platform). Current stable version is 0.6.2, last released in 2019. The package provides thin, type-safe bindings to fetch, Response, Headers, Request, AbortController, and FormData. It targets BuckleScript 5+ and is intended as a foundation for higher-level libraries. Unlike many other fetch bindings, it follows the ML naming conventions (e.g., `Response.type_` instead of `Response._type`) and requires a polyfill in Node.js. The package is no longer actively maintained; users should consider migrating to newer solutions like `promise-fetch` or direct `Js.Promise` + `fetch`.

devops

npm install bs-fetch

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · BS-FETCH

bs-fetch

devopsjavascriptv0.6.2

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

fetch

✓ let fetch = Fetch.fetch;

✗ let fetch = Bs_fetch.fetch;

Bs_fetch is deprecated since 0.2.0, use Fetch module instead.

Response

✓ open Fetch; let response = Response.make();

✗ let response = Bs_fetch.Response.make();

Use the Fetch module; Bs_fetch is deprecated.

Headers

✓ open Fetch; let headers = Headers.make();

✗ let headers = Fetch.Headers.makeWithDict(Js.Dict.fromList([("Content-Type", "application/json")]));

Headers.makeWithDict is available but make() with array pairs is more common in OCaml.

FormData

✓ open Fetch; let formData = FormData.make();

✗ let formData = Fetch.FormData.makeWithDict(...);

FormData was added in 0.6.2 and does not have a makeWithDict variant.

Shows how to use bs-fetch to perform a GET request and parse JSON response, including error handling and Node polyfill setup.

// Install: npm install bs-fetch // bsconfig.json: "bs-dependencies": ["bs-fetch"] // In your ReasonML file: let fetchJson = (url: string) => { open Fetch; Js.Promise.( Fetch.fetch(url) |> then_(Response.json) |> then_(json => { Js.log(json); resolve(json); }) |> catch(err => { Js.log2("Fetch failed", err); resolve(Js.Json.Null); }) ); }; // For Node.js, add at top entry file: [%raw "require('isomorphic-fetch')"];

Debug

Known issues

breakingIn 0.6.0, Response._type was renamed to Response.type_ to follow name mangling conventions.

fix

Replace all uses of `Response._type` with `Response.type_`.

affects: >=0.6.0

deprecatedThe module Bs_fetch is deprecated since 0.2.0. Use Fetch instead.

fix

Change `Bs_fetch.xxx` to `Fetch.xxx`.

affects: >=0.2.0

breakingIn 0.5.0, Headers.append and Headers.delete now return unit instead of being void.

fix

Ensure code that used the return values of these functions is updated.

affects: >=0.5.0

gotchaFetch API is not available in Node.js by default. You must provide a polyfill like isomorphic-fetch.

fix

Install isomorphic-fetch and add `[%raw "require('isomorphic-fetch')"]` at the top of your entry file.

affects: all

gotchaHeaders.makeWithDict is available only for OCaml users; ReasonML users may prefer Headers.make with array pairs.

fix

Use Headers.make([("key", "value")]) or Headers.makeWithDict(Js.Dict.fromList(...)) accordingly.

affects: >=0.3.0

deprecatedThe package is no longer actively maintained. Last release was 2019.

fix

Consider migrating to newer libraries like promise-fetch or directly using Js.Promise with the global fetch binding.

affects: all

Errors

Common errors & fixes

Error: Unbound module Bs_fetch

The deprecated Bs_fetch module is not available in newer versions; use Fetch instead.

fix

Replace `Bs_fetch` with `Fetch` in your code.

ReferenceError: fetch is not defined (Node.js)

fetch API is not available in Node.js without polyfill.

fix

Install isomorphic-fetch: `npm install isomorphic-fetch` and add `[%raw "require('isomorphic-fetch')"]` at the top of your main file.

Error: The variant type Response._type is not accessible (0.6.0+)

Response._type was renamed to Response.type_ in version 0.6.0.

fix

Use `Response.type_` instead of `Response._type`.

Error: Unbound value Headers.makeWithDict (pre-0.3.0)

Headers.makeWithDict was added in 0.3.0.

fix

Upgrade to bs-fetch >=0.3.0 or use Headers.make with array pairs.

Upgrade

Version history

0.6.2latest on npm

Audit

Dependencies

isomorphic-fetchoptionalRequired as a polyfill for Node.js since fetch is a Web API not available natively in Node.

bs-platformrequiredRequired as a peer dependency; the bindings rely on BuckleScript/bs-platform's Js module.

Agent activity

17 hits · last 30 days

node

Resources

githubhttps://github.com/reasonml-community/bs-fetch ↗

packagebs-fetch ↗

homepagehttps://github.com/reasonml-community/bs-fetch#readme ↗