feat: Accept more bodyInit types such as FormData, URLSearchParams, B…

…lob, ArrayBuffer, ReadableStream, etc

src/index.test.ts

@@ -162,11 +162,28 @@ describe('ensureStringBody', () => {
   })
 
   it('should return the same if body was not defined', () => {
-    expect(subject.ensureStringBody()).toBe(undefined)
+    expect(subject.ensureStringBody()).toBeUndefined()
   })
 
   it('should stringify the body if it is a JSON-like value', () => {
     expect(subject.ensureStringBody({ page: 2 })).toBe(`{"page":2}`)
+    expect(subject.ensureStringBody([1, 2])).toBe(`[1,2]`)
+    expect(subject.ensureStringBody(3)).toBe(`3`)
+    expect(subject.ensureStringBody(true)).toBe(`true`)
+    expect(subject.ensureStringBody({})).toBe(`{}`)
+  })
+
+  it('should not stringify other valid kinds of BodyInit', () => {
+    const ab = new ArrayBuffer(0)
+    expect(subject.ensureStringBody(ab)).toBe(ab)
+    const rs = new ReadableStream()
+    expect(subject.ensureStringBody(rs)).toBe(rs)
+    const fd = new FormData()
+    expect(subject.ensureStringBody(fd)).toBe(fd)
+    const usp = new URLSearchParams()
+    expect(subject.ensureStringBody(usp)).toBe(usp)
+    const blob = new Blob()
+    expect(subject.ensureStringBody(blob)).toBe(blob)
   })
 })
 

src/internals.ts

@@ -43,4 +43,32 @@ function replaceUrlParams(
   return url instanceof URL ? new URL(urlString) : urlString
 }
 
-export { getJson, getText, replaceUrlParams }
+/**
+ * This is an enhanced version of the typeof operator to check the type of more complex values.
+ * @param t the value to be checked
+ * @returns the type of the value
+ */
+function typeOf(t: unknown) {
+  return Object.prototype.toString
+    .call(t)
+    .replace(/^\[object (.+)\]$/, '$1')
+    .toLowerCase() as
+    | 'array'
+    | 'arraybuffer'
+    | 'bigint'
+    | 'blob'
+    | 'boolean'
+    | 'formdata'
+    | 'function'
+    | 'null'
+    | 'number'
+    | 'object'
+    | 'readablestream'
+    | 'string'
+    | 'symbol'
+    | 'undefined'
+    | 'url'
+    | 'urlsearchparams'
+}
+
+export { getJson, getText, replaceUrlParams, typeOf }

src/make-service.ts

@@ -1,5 +1,5 @@
 import { HTTP_METHODS } from './constants'
-import { getJson, getText, replaceUrlParams } from './internals'
+import { getJson, getText, replaceUrlParams, typeOf } from './internals'
 import {
   EnhancedRequestInit,
   HTTPMethod,
@@ -104,12 +104,19 @@ function typedResponse(response: Response): TypedResponse {
 
 /**
  * @param body the JSON-like body of the request
- * @returns the body stringified if it is not a string
+ * @returns the body is stringified if it is not a string and it is a JSON-like object. It also accepts other types of BodyInit such as Blob, ReadableStream, etc.
  */
-function ensureStringBody(body?: JSONValue): string | undefined {
-  if (typeof body === 'undefined') return
-  if (typeof body === 'string') return body
-  return JSON.stringify(body)
+function ensureStringBody<B extends JSONValue | BodyInit | null>(
+  body?: B,
+): B extends JSONValue ? string : B {
+  if (typeof body === 'undefined') return body as never
+  if (typeof body === 'string') return body as never
+
+  return (
+    ['number', 'boolean', 'array', 'object'].includes(typeOf(body))
+      ? JSON.stringify(body)
+      : body
+  ) as never
 }
 
 /**

src/types.ts

@@ -18,7 +18,7 @@ type TypedResponse = Omit<Response, 'json' | 'text'> & {
 }
 
 type EnhancedRequestInit = Omit<RequestInit, 'body'> & {
-  body?: JSONValue
+  body?: JSONValue | BodyInit | null
   query?: SearchParams
   params?: Record<string, string>
   trace?: (...args: Parameters<typeof fetch>) => void