feat: make the lib isomorphic (APIDevTools#280)

.eslintrc.yml

@@ -7,3 +7,5 @@ extends: "@jsdevtools"
 env:
   node: true
   browser: true
+rules:
+  "@typescript-eslint/no-explicit-any": ["off"]

.github/workflows/CI-CD.yaml

@@ -8,6 +8,8 @@ name: CI-CD
 
 on:
   push:
+    branches:
+      - main
   pull_request:
   schedule:
     - cron: "0 0 1 * *"
@@ -25,16 +27,16 @@ jobs:
           - macos-latest
           - windows-latest
         node:
-          - 10
-          - 12
           - 14
+          - lts/*
+          - current
 
     steps:
       - name: Checkout source
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install Node ${{ matrix.node }}
-        uses: actions/setup-node@v1
+        uses: actions/setup-node@v3
         with:
           node-version: ${{ matrix.node }}
 
@@ -69,12 +71,12 @@ jobs:
 
     steps:
       - name: Checkout source
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install Node
-        uses: actions/setup-node@v1
+        uses: actions/setup-node@v3
         with:
-          node-version: 12
+          node-version: lts/*
 
       - name: Install dependencies
         run: npm ci
@@ -120,10 +122,10 @@ jobs:
       - node_tests
       - browser_tests
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v1
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
         with:
-          node-version: 12
+          node-version: lts/*
 
       - name: Install dependencies
         run: npm ci

.mocharc.yml

@@ -7,3 +7,4 @@ spec: test/specs/**/*.spec.js
 bail: true
 recursive: true
 async-only: true
+require: ./test/fixtures/polyfill.js

README.md

@@ -111,6 +111,13 @@ When using a transpiler such as [Babel](https://babeljs.io/) or [TypeScript](htt
 import $RefParser from "@apidevtools/json-schema-ref-parser";
 ```
 
+If you are using Node.js < 18, you'll need a polyfill for `fetch`, like [node-fetch](https://github.com/node-fetch/node-fetch):
+```javascript
+import fetch from "node-fetch";
+
+globalThis.fetch = fetch;
+```
+
 
 
 Browser support

lib/resolvers/http.js

@@ -1,7 +1,5 @@
 "use strict";
 
-const http = require("http");
-const https = require("https");
 const { ono } = require("@jsdevtools/ono");
 const url = require("../util/url");
 const { ResolverError } = require("../util/errors");
@@ -70,12 +68,12 @@ module.exports = {
    * @param {object} file           - An object containing information about the referenced file
    * @param {string} file.url       - The full URL of the referenced file
    * @param {string} file.extension - The lowercased file extension (e.g. ".txt", ".html", etc.)
-   * @returns {Promise<Buffer>}
+   * @returns {Promise<string>}
    */
   read (file) {
     let u = url.parse(file.url);
 
-    if (process.browser && !u.protocol) {
+    if (typeof window !== "undefined" && !u.protocol) {
       // Use the protocol of the current page
       u.protocol = url.parse(location.href).protocol;
     }
@@ -91,42 +89,40 @@ module.exports = {
  * @param {object} httpOptions  - The `options.resolve.http` object
  * @param {number} [redirects]  - The redirect URLs that have already been followed
  *
- * @returns {Promise<Buffer>}
+ * @returns {Promise<string>}
  * The promise resolves with the raw downloaded data, or rejects if there is an HTTP error.
  */
 function download (u, httpOptions, redirects) {
-  return new Promise(((resolve, reject) => {
-    u = url.parse(u);
-    redirects = redirects || [];
-    redirects.push(u.href);
-
-    get(u, httpOptions)
-      .then((res) => {
-        if (res.statusCode >= 400) {
-          throw ono({ status: res.statusCode }, `HTTP ERROR ${res.statusCode}`);
+  u = url.parse(u);
+  redirects = redirects || [];
+  redirects.push(u.href);
+
+  return get(u, httpOptions)
+    .then((res) => {
+      if (res.statusCode >= 400) {
+        throw ono({ status: res.statusCode }, `HTTP ERROR ${res.statusCode}`);
+      }
+      else if (res.statusCode >= 300) {
+        if (redirects.length > httpOptions.redirects) {
+          throw new ResolverError(ono({ status: res.statusCode },
+            `Error downloading ${redirects[0]}. \nToo many redirects: \n  ${redirects.join(" \n  ")}`));
         }
-        else if (res.statusCode >= 300) {
-          if (redirects.length > httpOptions.redirects) {
-            reject(new ResolverError(ono({ status: res.statusCode },
-              `Error downloading ${redirects[0]}. \nToo many redirects: \n  ${redirects.join(" \n  ")}`)));
-          }
-          else if (!res.headers.location) {
-            throw ono({ status: res.statusCode }, `HTTP ${res.statusCode} redirect with no location header`);
-          }
-          else {
-            // console.log('HTTP %d redirect %s -> %s', res.statusCode, u.href, res.headers.location);
-            let redirectTo = url.resolve(u, res.headers.location);
-            download(redirectTo, httpOptions, redirects).then(resolve, reject);
-          }
+        else if (!res.headers.location) {
+          throw ono({ status: res.statusCode }, `HTTP ${res.statusCode} redirect with no location header`);
         }
         else {
-          resolve(res.body || Buffer.alloc(0));
+          // console.log('HTTP %d redirect %s -> %s', res.statusCode, u.href, res.headers.location);
+          let redirectTo = url.resolve(u, res.headers.location);
+          return download(redirectTo, httpOptions, redirects);
         }
-      })
-      .catch((err) => {
-        reject(new ResolverError(ono(err, `Error downloading ${u.href}`), u.href));
-      });
-  }));
+      }
+      else {
+        return res.text();
+      }
+    })
+    .catch((err) => {
+      throw new ResolverError(ono(err, `Error downloading ${u.href}`), u.href);
+    });
 }
 
 /**
@@ -139,42 +135,23 @@ function download (u, httpOptions, redirects) {
  * The promise resolves with the HTTP Response object.
  */
 function get (u, httpOptions) {
-  return new Promise(((resolve, reject) => {
-    // console.log('GET', u.href);
-
-    let protocol = u.protocol === "https:" ? https : http;
-    let req = protocol.get({
-      hostname: u.hostname,
-      port: u.port,
-      path: u.path,
-      auth: u.auth,
-      protocol: u.protocol,
-      headers: httpOptions.headers || {},
-      withCredentials: httpOptions.withCredentials
-    });
+  let controller;
+  let timeoutId;
+  if (httpOptions.timeout) {
+    controller = new AbortController();
+    timeoutId = setTimeout(() => controller.abort(), httpOptions.timeout);
+  }
 
-    if (typeof req.setTimeout === "function") {
-      req.setTimeout(httpOptions.timeout);
+  return fetch(u, {
+    method: "GET",
+    headers: httpOptions.headers || {},
+    credentials: httpOptions.withCredentials ? "include" : "same-origin",
+    signal: controller ? controller.signal : null,
+  }).then(response => {
+    if (timeoutId) {
+      clearTimeout(timeoutId);
     }
 
-    req.on("timeout", () => {
-      req.abort();
-    });
-
-    req.on("error", reject);
-
-    req.once("response", (res) => {
-      res.body = Buffer.alloc(0);
-
-      res.on("data", (data) => {
-        res.body = Buffer.concat([res.body, Buffer.from(data)]);
-      });
-
-      res.on("error", reject);
-
-      res.on("end", () => {
-        resolve(res);
-      });
-    });
-  }));
+    return response;
+  });
 }

lib/util/url.js

@@ -1,6 +1,6 @@
 "use strict";
 
-let isWindows = /^win/.test(process.platform),
+let isWindows = /^win/.test(globalThis.process?.platform),
     forwardSlashPattern = /\//g,
     protocolPattern = /^(\w{2,}):\/\//i,
     url = module.exports,
@@ -22,7 +22,7 @@ let urlDecodePatterns = [
   /\%40/g, "@"
 ];
 
-exports.parse = require("url").parse;
+exports.parse = (u) => new URL(u);
 
 /**
  * Returns resolved target URL relative to a base URL in a manner similar to that of a Web browser resolving an anchor tag HREF.
@@ -45,7 +45,7 @@ exports.resolve = function resolve (from, to) {
  * @returns {string}
  */
 exports.cwd = function cwd () {
-  if (process.browser) {
+  if (typeof window !== "undefined") {
     return location.href;
   }
 
@@ -144,7 +144,7 @@ exports.isHttp = function isHttp (path) {
   }
   else if (protocol === undefined) {
     // There is no protocol.  If we're running in a browser, then assume it's HTTP.
-    return process.browser;
+    return typeof window !== "undefined";
   }
   else {
     // It's some other protocol, such as "ftp://", "mongodb://", etc.