ES Modules (#295)

* Update package-lock.json file

* Fix broken tests in blank.spec.js

Blank binary file was not getting serialized as { type: "Buffer", data: [] }
because read(file) was returning a string instead of Buffer.

* Fix webpack error when running browser tests

Webpack 4 cannot parse module containing optional chaining operator.
See https://stackoverflow.com/questions/59972341/how-to-make-webpack-accept-optional-chaining-without-babel

* Fix tests in invalid.spec.js when running in Chrome

* Change statusCode to status

* Set the --openssl-legacy-provider flag when running browser tests

Recent versions of node upgraded to OpenSSL 3.0, which deprecated some
older crypto hashing algorithms including md4.

Webpack 4 hard codes the use of md4 ins some places, so we have to set this
flag until we can upgrade Webpack.

* Use isomorphic-fetch instead of node-fetch

Browser tests were failing as polyfill.js was loading a node package in a browser context.

* Increase minimum version of node to 17

This was when the --openssl-legacy-provider option was introduced.
Prior versions of node do not recognize this option.

* Add chokidar@3 as an explicit dev dependency

Browser tests are failing in the CI environment with:
chokidar@3: Error: Cannot find module 'chokidar'

Don't know why but this thread might be relevant:
facebook/create-react-app#10811

* Skip test assertion due to conflict on Windows

See also #286

* Explicitly define browsers and plugins in karma.conf.js

* Replace karma-edge-launcher with newer package

* Increase default timeout of async tests

* Change package type to module

* Change require/module.exports to import/export in source files

* Delete "use strict" directives from source code

* Update tests to ES modules

* Re-export $RefParser methods as standalone functions

Preserve backwards compatibility

* Make karma config file a .cjs file

Fixes “require() of ES Module …/config.js not supported” error

* Avoid top-level await in path.js

The current configuration of karma uses Webpack 4, which can't parse
modules with top-level await.

* Revert back to __dirname for browser tests

Karma configuration needs to upgrade to Webpack 5 in order to use import.meta.url

* Fix lint issues

* Disable code coverage in CI for now

* Revert "Disable code coverage in CI for now"

This reverts commit f571f0a.

* Replace nyc with c8 to work with ES modules

* Implement a dual CommonJS/ES module package.json

* Hack to allow $RefParser to be imported from require() without .default property

Without this hack, you would have to do this:

const $RefParser = require("@apidevtools/json-schema-ref-parser).default;

Now you can do this:

const $RefParser = require("@apidevtools/json-schema-ref-parser);

Author: jcmosc

Diff for: .c8rc.json

@@ -0,0 +1,4 @@
+{
+  "extension": [".js", ".cjs", ".mjs", ".ts"],
+  "reporter": ["text", "lcov"]
+}

Diff for: .eslintrc.yml

@@ -9,3 +9,5 @@ env:
   browser: true
 rules:
   "@typescript-eslint/no-explicit-any": ["off"]
+parserOptions:
+  sourceType: module

Diff for: .mocharc.yml

@@ -7,4 +7,5 @@ spec: test/specs/**/*.spec.js
 bail: true
 recursive: true
 async-only: true
+timeout: "5000"
 require: ./test/fixtures/polyfill.js

Diff for: .nycrc.yml

@@ -0,0 +1,18 @@
+{
+  "$schema": "http://json.schemastore.org/swcrc",
+  "jsc": {
+    "parser": {
+      "syntax": "ecmascript",
+      "exportDefaultFrom": true
+    }
+  },
+  "module": {
+    "type": "commonjs",
+
+    // These are defaults.
+    "strict": false,
+    "strictMode": true,
+    "lazy": false,
+    "noInterop": false
+  }
+}

Diff for: .swcrc

@@ -45,6 +45,11 @@ module.exports = (karma) => {
     }
   });
 
+  config.files.push({
+    pattern: "test/**/*.js",
+    type: "module"
+  });
+
   if (config.logLevel !== karma.LOG_DISABLE) {
     console.debug("Karma Config:\n", nodeUtil.inspect(config, {
       depth: 10,

Diff for: karma.conf.js renamed to karma.conf.cjs

@@ -1,10 +1,8 @@
-"use strict";
+import $Ref from "./ref.js";
+import Pointer from "./pointer.js";
+import * as url from "./util/url.js";
 
-const $Ref = require("./ref");
-const Pointer = require("./pointer");
-const url = require("./util/url");
-
-module.exports = bundle;
+export default bundle;
 
 /**
  * Bundles all external JSON references into the main JSON schema, thus resulting in a schema that

Diff for: lib/bundle.js

@@ -1,11 +1,9 @@
-"use strict";
+import $Ref from "./ref.js";
+import Pointer from "./pointer.js";
+import { ono } from "@jsdevtools/ono";
+import * as url from "./util/url.js";
 
-const $Ref = require("./ref");
-const Pointer = require("./pointer");
-const { ono } = require("@jsdevtools/ono");
-const url = require("./util/url");
-
-module.exports = dereference;
+export default dereference;
 
 /**
  * Crawls the JSON schema, finds all JSON references, and dereferences them.

Diff for: lib/dereference.js

@@ -1,26 +1,23 @@
 /* eslint-disable no-unused-vars */
-"use strict";
+import $Refs from "./refs.js";
+import _parse from "./parse.js";
+import normalizeArgs from "./normalize-args.js";
+import resolveExternal from "./resolve-external.js";
+import _bundle from "./bundle.js";
+import _dereference from "./dereference.js";
+import * as url from "./util/url.js";
+import { JSONParserError, InvalidPointerError, MissingPointerError, ResolverError, ParserError, UnmatchedParserError, UnmatchedResolverError, isHandledError, JSONParserErrorGroup } from "./util/errors.js";
+import maybe from "call-me-maybe";
+import { ono } from "@jsdevtools/ono";
 
-const $Refs = require("./refs");
-const _parse = require("./parse");
-const normalizeArgs = require("./normalize-args");
-const resolveExternal = require("./resolve-external");
-const _bundle = require("./bundle");
-const _dereference = require("./dereference");
-const url = require("./util/url");
-const { JSONParserError, InvalidPointerError, MissingPointerError, ResolverError, ParserError, UnmatchedParserError, UnmatchedResolverError, isHandledError, JSONParserErrorGroup } = require("./util/errors");
-const maybe = require("call-me-maybe");
-const { ono } = require("@jsdevtools/ono");
-
-module.exports = $RefParser;
-module.exports.default = $RefParser;
-module.exports.JSONParserError = JSONParserError;
-module.exports.InvalidPointerError = InvalidPointerError;
-module.exports.MissingPointerError = MissingPointerError;
-module.exports.ResolverError = ResolverError;
-module.exports.ParserError = ParserError;
-module.exports.UnmatchedParserError = UnmatchedParserError;
-module.exports.UnmatchedResolverError = UnmatchedResolverError;
+export default $RefParser;
+export { JSONParserError };
+export { InvalidPointerError };
+export { MissingPointerError };
+export { ResolverError };
+export { ParserError };
+export { UnmatchedParserError };
+export { UnmatchedResolverError };
 
 /**
  * This class parses a JSON schema, builds a map of its JSON references and their resolved values,
@@ -281,3 +278,13 @@ function finalize (parser) {
     throw new JSONParserErrorGroup(parser);
   }
 }
+
+export const parse = $RefParser.parse.bind($RefParser);
+export const resolve = $RefParser.resolve.bind($RefParser);
+export const bundle = $RefParser.bundle.bind($RefParser);
+export const dereference = $RefParser.dereference.bind($RefParser);
+
+// CommonJS default export hack
+if (typeof module === "object" && typeof module.exports === "object") {
+  module.exports = Object.assign(module.exports.default, module.exports);
+}

Diff for: lib/index.js

@@ -1,8 +1,6 @@
-"use strict";
+import Options from "./options.js";
 
-const Options = require("./options");
-
-module.exports = normalizeArgs;
+export default normalizeArgs;
 
 /**
  * Normalizes the given arguments, accounting for optional args.

Diff for: lib/normalize-args.js

@@ -1,14 +1,12 @@
 /* eslint lines-around-comment: [2, {beforeBlockComment: false}] */
-"use strict";
+import jsonParser from "./parsers/json.js";
+import yamlParser from "./parsers/yaml.js";
+import textParser from "./parsers/text.js";
+import binaryParser from "./parsers/binary.js";
+import fileResolver from "./resolvers/file.js";
+import httpResolver from "./resolvers/http.js";
 
-const jsonParser = require("./parsers/json");
-const yamlParser = require("./parsers/yaml");
-const textParser = require("./parsers/text");
-const binaryParser = require("./parsers/binary");
-const fileResolver = require("./resolvers/file");
-const httpResolver = require("./resolvers/http");
-
-module.exports = $RefParserOptions;
+export default $RefParserOptions;
 
 /**
  * Options that determine how JSON schemas are parsed, resolved, and dereferenced.

Diff for: lib/options.js

@@ -1,11 +1,9 @@
-"use strict";
+import { ono } from "@jsdevtools/ono";
+import * as url from "./util/url.js";
+import * as plugins from "./util/plugins.js";
+import { ResolverError, ParserError, UnmatchedParserError, UnmatchedResolverError, isHandledError } from "./util/errors.js";
 
-const { ono } = require("@jsdevtools/ono");
-const url = require("./util/url");
-const plugins = require("./util/plugins");
-const { ResolverError, ParserError, UnmatchedParserError, UnmatchedResolverError, isHandledError } = require("./util/errors");
-
-module.exports = parse;
+export default parse;
 
 /**
  * Reads and parses the specified file path or URL.

Diff for: lib/parse.js

@@ -1,8 +1,6 @@
-"use strict";
-
 let BINARY_REGEXP = /\.(jpeg|jpg|gif|png|bmp|ico)$/i;
 
-module.exports = {
+export default {
   /**
    * The order that this parser will run, in relation to other parsers.
    *

Diff for: lib/parsers/binary.js

@@ -1,8 +1,6 @@
-"use strict";
+import { ParserError } from "../util/errors.js";
 
-const { ParserError } = require("../util/errors");
-
-module.exports = {
+export default {
   /**
    * The order that this parser will run, in relation to other parsers.
    *

Diff for: lib/parsers/json.js

@@ -1,10 +1,8 @@
-"use strict";
-
-const { ParserError } = require("../util/errors");
+import { ParserError } from "../util/errors.js";
 
 let TEXT_REGEXP = /\.(txt|htm|html|md|xml|js|min|map|css|scss|less|svg)$/i;
 
-module.exports = {
+export default {
   /**
    * The order that this parser will run, in relation to other parsers.
    *

Diff for: lib/parsers/text.js

@@ -1,10 +1,8 @@
-"use strict";
+import { ParserError } from "../util/errors.js";
+import yaml from "js-yaml";
+import { JSON_SCHEMA } from "js-yaml";
 
-const { ParserError } = require("../util/errors");
-const yaml = require("js-yaml");
-const { JSON_SCHEMA } = require("js-yaml");
-
-module.exports = {
+export default {
   /**
    * The order that this parser will run, in relation to other parsers.
    *

Diff for: lib/parsers/yaml.js

@@ -1,10 +1,8 @@
-"use strict";
+export default Pointer;
 
-module.exports = Pointer;
-
-const $Ref = require("./ref");
-const url = require("./util/url");
-const { JSONParserError, InvalidPointerError, MissingPointerError, isHandledError } = require("./util/errors");
+import $Ref from "./ref.js";
+import * as url from "./util/url.js";
+import { JSONParserError, InvalidPointerError, MissingPointerError, isHandledError } from "./util/errors.js";
 const slashes = /\//g;
 const tildes = /~/g;
 const escapedSlash = /~1/g;

Diff for: lib/pointer.js

@@ -1,10 +1,8 @@
-"use strict";
+export default $Ref;
 
-module.exports = $Ref;
-
-const Pointer = require("./pointer");
-const { InvalidPointerError, isHandledError, normalizeError } = require("./util/errors");
-const { safePointerToPath, stripHash, getHash } = require("./util/url");
+import Pointer from "./pointer.js";
+import { InvalidPointerError, isHandledError, normalizeError } from "./util/errors.js";
+import { safePointerToPath, stripHash, getHash } from "./util/url.js";
 
 /**
  * This class represents a single JSON reference and its resolved value.

Diff for: lib/ref.js

@@ -1,18 +1,14 @@
-"use strict";
-
-const { ono } = require("@jsdevtools/ono");
-const $Ref = require("./ref");
-const url = require("./util/url");
+import { ono } from "@jsdevtools/ono";
+import $Ref from "./ref.js";
+import * as url from "./util/url.js";
 
 const isWindows = /^win/.test(globalThis.process ? globalThis.process.platform : undefined);
 const getPathFromOs = filePath => isWindows ? filePath.replace(/\\/g, "/") : filePath;
 
-module.exports = $Refs;
-
 /**
  * This class is a map of JSON references and their resolved values.
  */
-function $Refs () {
+export default function $Refs () {
   /**
    * Indicates whether the schema contains any circular references.
    *

Diff for: lib/refs.js

@@ -1,12 +1,10 @@
-"use strict";
+import $Ref from "./ref.js";
+import Pointer from "./pointer.js";
+import parse from "./parse.js";
+import * as url from "./util/url.js";
+import { isHandledError } from "./util/errors.js";
 
-const $Ref = require("./ref");
-const Pointer = require("./pointer");
-const parse = require("./parse");
-const url = require("./util/url");
-const { isHandledError } = require("./util/errors");
-
-module.exports = resolveExternal;
+export default resolveExternal;
 
 /**
  * Crawls the JSON schema, finds all external JSON references, and resolves their values.

Diff for: lib/resolve-external.js

@@ -1,10 +1,9 @@
-"use strict";
-const fs = require("fs");
-const { ono } = require("@jsdevtools/ono");
-const url = require("../util/url");
-const { ResolverError } = require("../util/errors");
+import fs from "fs";
+import { ono } from "@jsdevtools/ono";
+import * as url from "../util/url.js";
+import { ResolverError } from "../util/errors.js";
 
-module.exports = {
+export default {
   /**
    * The order that this resolver will run, in relation to other resolvers.
    *

Diff for: lib/resolvers/file.js

@@ -1,10 +1,8 @@
-"use strict";
+import { ono } from "@jsdevtools/ono";
+import * as url from "../util/url.js";
+import { ResolverError } from "../util/errors.js";
 
-const { ono } = require("@jsdevtools/ono");
-const url = require("../util/url");
-const { ResolverError } = require("../util/errors");
-
-module.exports = {
+export default {
   /**
    * The order that this resolver will run, in relation to other resolvers.
    *