Fix eslint issue

Author: octet-stream

lib/FormDataEncoder.test.ts

@@ -106,6 +106,26 @@ test("Has contentLength property", async t => {
   )
 })
 
+test(
+  "contentLength property is undefined if there's file without known length",
+
+  t => {
+    const form = new FormData()
+
+    form.set("stream", {
+      [Symbol.toStringTag]: "File",
+      name: "file.txt",
+      stream() {
+        return Readable.from([Buffer.from("foo")])
+      }
+    })
+
+    const encoder = new FormDataEncoder(form)
+
+    t.is(encoder.contentLength, undefined)
+  }
+)
+
 test("contentLength property is read-only", t => {
   const encoder = new FormDataEncoder(new FormData())
 
@@ -137,6 +157,28 @@ test("Has correct headers", async t => {
   })
 })
 
+test(
+  "Has only Content-Type header if there's file without known length",
+
+  t => {
+    const form = new FormData()
+
+    form.set("stream", {
+      [Symbol.toStringTag]: "File",
+      name: "file.txt",
+      stream() {
+        return Readable.from([Buffer.from("foo")])
+      }
+    })
+
+    const encoder = new FormDataEncoder(form)
+
+    t.deepEqual(encoder.headers, {
+      "Content-Type": `multipart/form-data; boundary=${encoder.boundary}`
+    })
+  }
+)
+
 test("Yields correct footer for empty FormData", async t => {
   const encoder = new FormDataEncoder(new FormData())
 
@@ -157,7 +199,7 @@ test("Returns correct length of the empty FormData content", async t => {
   const encoder = new FormDataEncoder(new FormData())
   const expected = await readStream(encoder).then(({length}) => length)
 
-  t.is<number>(encoder.getContentLength(), expected)
+  t.is(encoder.getContentLength(), expected)
 })
 
 test("Returns the length of the FormData content", async t => {
@@ -170,9 +212,29 @@ test("Returns the length of the FormData content", async t => {
 
   const expected = await readStream(encoder).then(({length}) => length)
 
-  t.is<number>(encoder.getContentLength(), expected)
+  t.is(encoder.getContentLength(), expected)
 })
 
+test(
+  ".getContentLength() returns undefined if there's file without known length",
+
+  t => {
+    const form = new FormData()
+
+    form.set("stream", {
+      [Symbol.toStringTag]: "File",
+      name: "file.txt",
+      stream() {
+        return Readable.from([Buffer.from("foo")])
+      }
+    })
+
+    const encoder = new FormDataEncoder(form)
+
+    t.is(encoder.getContentLength(), undefined)
+  }
+)
+
 test(".values() yields headers as Uint8Array", t => {
   const form = new FormData()
 
@@ -329,6 +391,41 @@ test(
   }
 )
 
+test(
+  "Does not imclude Content-Length header with enableAdditionalHeaders "
+    + "option if entry does not have known length",
+
+  async t => {
+    const form = new FormData()
+
+    form.set("stream", {
+      [Symbol.toStringTag]: "File",
+      name: "file.txt",
+      stream() {
+        return Readable.from([Buffer.from("foo")])
+      }
+    })
+
+    const encoder = new FormDataEncoder(form, {
+      enableAdditionalHeaders: true
+    })
+
+    const iterable = readLine(Readable.from(encoder))
+
+    await skip(iterable, 1)
+    const headers: string[] = []
+    for await (const chunk of iterable) {
+      if (chunk === "") {
+        break
+      }
+
+      headers.push(chunk.split(":")[0].toLowerCase())
+    }
+
+    t.false(headers.includes("content-length"))
+  }
+)
+
 test("Yields File's content", async t => {
   const filePath = "license"
   const form = new FormData()
@@ -354,7 +451,7 @@ test("Yields File's content", async t => {
   chunks.pop() // Remove trailing empty line
 
   // It looks like files on Windows have different EOL when you read them, even though they were created on macOS x)
-  t.is<string>(chunks.join(EOL), expected)
+  t.is(chunks.join(EOL), expected)
 })
 
 test("Yields every appended field", async t => {

lib/FormDataEncoder.ts

@@ -1,3 +1,5 @@
+/* eslint-disable no-restricted-globals */
+
 import createBoundary from "./util/createBoundary"
 import isPlainObject from "./util/isPlainObject"
 import normalize from "./util/normalizeValue"
@@ -8,6 +10,11 @@ import {isFormData} from "./util/isFormData"
 import {FormDataLike} from "./FormDataLike"
 import {FileLike} from "./FileLike"
 
+interface Headers {
+  "Content-Type": string
+  "Content-Length"?: string
+}
+
 export interface FormDataEncoderOptions {
   /**
    * When enabled, the encoder will emit additional per part headers, such as `Content-Length`.
@@ -66,15 +73,12 @@ export class FormDataEncoder {
   /**
    * Returns Content-Length header
    */
-  readonly contentLength: string
+  readonly contentLength: string | undefined
 
   /**
    * Returns headers object with Content-Type and Content-Length header
    */
-  readonly headers: {
-    "Content-Type": string
-    "Content-Length": string
-  }
+  readonly headers: Readonly<Headers>
 
   /**
    * Creates a multipart/form-data encoder.
@@ -163,12 +167,17 @@ export class FormDataEncoder {
       `${this.#DASHES}${this.boundary}${this.#DASHES}${this.#CRLF.repeat(2)}`
     )
 
-    this.contentLength = String(this.getContentLength())
+    const contentLength = this.getContentLength()
+    const headers: Headers = {
+      "Content-Type": this.contentType
+    }
 
-    this.headers = Object.freeze({
-      "Content-Type": this.contentType,
-      "Content-Length": this.contentLength
-    })
+    if (contentLength != null) {
+      this.contentLength = String(contentLength)
+      headers["Content-Length"] = this.contentLength
+    }
+
+    this.headers = Object.freeze(headers)
 
     // Make sure following properties read-only in runtime.
     Object.defineProperties(this, {
@@ -191,9 +200,10 @@ export class FormDataEncoder {
     }
 
     if (this.#options.enableAdditionalHeaders === true) {
-      header += `${this.#CRLF}Content-Length: ${
-        isFileLike(value) ? value.size : value.byteLength
-      }`
+      const size = isFileLike(value) ? value.size : value.byteLength
+      if (size != null && !isNaN(size)) {
+        header += `${this.#CRLF}Content-Length: ${size}`
+      }
     }
 
     return this.#encoder.encode(`${header}${this.#CRLF.repeat(2)}`)
@@ -202,15 +212,22 @@ export class FormDataEncoder {
   /**
    * Returns form-data content length
    */
-  getContentLength(): number {
+  getContentLength(): number | undefined {
     let length = 0
 
     for (const [name, raw] of this.#form) {
       const value = isFileLike(raw) ? raw : this.#encoder.encode(normalize(raw))
 
+      const size = isFileLike(value) ? value.size : value.byteLength
+
+      // Return `undefined` if encountered part without known size
+      if (size == null || isNaN(size)) {
+        return undefined
+      }
+
       length += this.#getFieldHeader(name, value).byteLength
 
-      length += isFileLike(value) ? value.size : value.byteLength
+      length += size
 
       length += this.#CRLF_BYTES_LENGTH
     }

lib/util/isFileLike.test.ts

@@ -56,6 +56,23 @@ test("Returns true for a file-shaped object", t => {
   t.true(isFileLike(object))
 })
 
+test("Returns true for minimal valid file-ish object shape", t => {
+  // eslint-disable-next-line max-len
+  const object: Pick<FileLike, "name" | "stream" | typeof Symbol.toStringTag> = {
+    name: "",
+
+    async* stream(): AsyncGenerator<Uint8Array> {
+      yield new Uint8Array(0)
+    },
+
+    get [Symbol.toStringTag](): string {
+      return "File"
+    }
+  }
+
+  t.true(isFileLike(object))
+})
+
 test("Returns false for null", t => {
   t.false(isFileLike(null))
 })

lib/util/isFileLike.ts

@@ -28,13 +28,11 @@ import {FileLike} from "../FileLike"
  * isFileLike(fs.createReadStream("path/to/a/file.txt")) // -> false
  * ```
  */
-export const isFileLike = (value?: unknown): value is FileLike => Boolean(
+export const isFileLike = (value: unknown): value is FileLike => Boolean(
   (value as FileLike)
     && typeof (value as FileLike) === "object"
     && isFunction((value as FileLike).constructor)
     && (value as FileLike)[Symbol.toStringTag] === "File"
     && isFunction((value as FileLike).stream)
     && (value as FileLike).name != null
-    && (value as FileLike).size != null
-    && (value as FileLike).lastModified != null
 )

package.json

@@ -30,8 +30,7 @@
     "build:types": "ttsc --project tsconfig.d.ts.json",
     "build": "npm run build:esm && npm run build:cjs && npm run build:types",
     "test": "ava --fail-fast",
-    "cleanup": "npx rimraf @type \"lib/**/*.js\"",
-    "prepare": "npm run cleanup && npm run build",
+    "cleanup": "npx del-cli @type \"lib/**/*.js\"",
     "postinstall": "husky install",
     "prepublishOnly": "pinst --disable",
     "postpublish": "pinst --enable"
@@ -47,6 +46,7 @@
     "@zoltu/typescript-transformer-append-js-extension": "1.0.1",
     "ava": "4.2.0",
     "c8": "7.11.2",
+    "del-cli": "5.0.0",
     "eslint": "7.32.0",
     "eslint-config-airbnb-typescript": "12.3.1",
     "eslint-plugin-ava": "12.0.0",