fix: esm json import

lib/index.ts

@@ -8,11 +8,11 @@
  */
 
 import { format } from 'util'
-import { readFileSync } from 'fs'
 import { normalize, resolve } from 'path'
 import { ArgsInput, Arguments, Parser, Options, DetailedArguments } from './yargs-parser-types.js'
 import { camelCase, decamelize, looksLikeNumber } from './string-utils.js'
 import { YargsParser } from './yargs-parser.js'
+import { readFileSync } from 'fs'
 
 // See https://github.com/yargs/yargs-parser#supported-nodejs-versions for our
 // version support policy. The YARGS_MIN_NODE_VERSION is used for testing only.
@@ -42,7 +42,8 @@ const parser = new YargsParser({
     if (typeof require !== 'undefined') {
       return require(path)
     } else if (path.match(/\.json$/)) {
-      return readFileSync(path, 'utf8')
+      // Addresses: https://github.com/yargs/yargs/issues/2040
+      return JSON.parse(readFileSync(path, 'utf8'))
     } else {
       throw Error('only .json config files are supported in ESM')
     }

package.json

@@ -19,6 +19,7 @@
     "fix": "standardx --fix '**/*.ts' && standardx --fix '**/*.js' && standardx --fix '**/*.cjs'",
     "pretest": "rimraf build && tsc -p tsconfig.test.json && cross-env NODE_ENV=test npm run build:cjs",
     "test": "c8 --reporter=text --reporter=html mocha test/*.cjs",
+    "test:esm": "c8 --reporter=text --reporter=html mocha test/*.mjs",
     "test:browser": "start-server-and-test 'serve ./ -p 8080' http://127.0.0.1:8080/package.json 'node ./test/browser/yargs-test.cjs'",
     "pretest:typescript": "npm run pretest",
     "test:typescript": "c8 mocha ./build/test/typescript/*.js",
@@ -49,7 +50,7 @@
   "devDependencies": {
     "@types/chai": "^4.2.11",
     "@types/mocha": "^9.0.0",
-    "@types/node": "^16.0.0",
+    "@types/node": "^16.11.4",
     "@typescript-eslint/eslint-plugin": "^3.10.1",
     "@typescript-eslint/parser": "^3.10.1",
     "@wessberg/rollup-plugin-ts": "^1.2.28",

test/tscc/package.json

@@ -3,6 +3,6 @@
   "version": "0.0.0",
   "dependencies": {
     "@tscc/tscc": "^0.7.4",
-    "@types/node": "^10.0.3"
+    "@types/node": "^16.11.4"
   }
 }

test/tscc/tsconfig.json

@@ -1,5 +1,6 @@
 {
   "compilerOptions": {
+    "module": "es2020",
     "target": "es2017",
     "moduleResolution": "node"
   },  

test/yargs-parser.mjs

@@ -0,0 +1,264 @@
+import { should, expect } from 'chai'
+import parser from '../build/lib/index.js'
+import path from 'path'
+import { fileURLToPath } from 'url'
+import { readFileSync } from 'fs'
+
+should()
+
+describe('yargs-parser (esm)', function () {
+  const __dirname = path.dirname(fileURLToPath(import.meta.url))
+  const jsonPath = path.resolve(__dirname, './fixtures/config.json')
+  describe('config', function () {
+    it('should load options and values from default config if specified', function () {
+      const argv = parser(['--foo', 'bar'], {
+        alias: {
+          z: 'zoom'
+        },
+        default: {
+          settings: jsonPath
+        },
+        config: 'settings'
+      })
+
+      argv.should.have.property('herp', 'derp')
+      argv.should.have.property('zoom', 55)
+      argv.should.have.property('foo').and.deep.equal('bar')
+    })
+
+    it('should use value from config file, if argv value is using default value', function () {
+      const argv = parser([], {
+        alias: {
+          z: 'zoom'
+        },
+        config: ['settings'],
+        default: {
+          settings: jsonPath,
+          foo: 'banana'
+        }
+      })
+
+      argv.should.have.property('herp', 'derp')
+      argv.should.have.property('zoom', 55)
+      argv.should.have.property('foo').and.deep.equal('baz')
+    })
+
+    it('should combine values from config file and argv, if argv value is an array', function () {
+      const argv = parser(['--foo', 'bar'], {
+        config: ['settings'],
+        array: ['foo'],
+        default: {
+          settings: jsonPath
+        },
+        configuration: {
+          'combine-arrays': true
+        }
+      })
+
+      argv.should.have.property('foo').and.deep.equal(['bar', 'baz'])
+    })
+
+    it('should use value from config file, if argv key is a boolean', function () {
+      const argv = parser([], {
+        config: ['settings'],
+        default: {
+          settings: jsonPath
+        },
+        boolean: ['truthy']
+      })
+
+      argv.should.have.property('truthy', true)
+    })
+
+    it('should use value from cli, if cli overrides boolean argv key', function () {
+      const argv = parser(['--no-truthy'], {
+        config: ['settings'],
+        default: {
+          settings: jsonPath
+        },
+        boolean: ['truthy']
+      })
+
+      argv.should.have.property('truthy', false)
+    })
+
+    it('should use cli value, if cli value is set and both cli and default value match', function () {
+      const argv = parser(['--foo', 'banana'], {
+        alias: {
+          z: 'zoom'
+        },
+        config: ['settings'],
+        default: {
+          settings: jsonPath,
+          foo: 'banana'
+        }
+      })
+
+      argv.should.have.property('herp', 'derp')
+      argv.should.have.property('zoom', 55)
+      argv.should.have.property('foo').and.deep.equal('banana')
+    })
+
+    it("should allow config to be set as flag in 'option'", function () {
+      const argv = parser(['--settings', jsonPath, '--foo', 'bar'], {
+        alias: {
+          z: 'zoom'
+        },
+        config: ['settings']
+      })
+
+      argv.should.have.property('herp', 'derp')
+      argv.should.have.property('zoom', 55)
+      argv.should.have.property('foo').and.deep.equal('bar')
+    })
+
+    // for esm, only support importing json files
+    it('should fail to load options and values from a JS file when config has .js extention', function () {
+      const jsPath = path.resolve(__dirname, './fixtures/settings.cjs')
+      const argv = parser.detailed(['--settings', jsPath, '--foo', 'bar'], {
+        config: ['settings']
+      })
+
+      argv.error.message.should.include('Invalid JSON config file')
+    })
+
+    it('should raise an appropriate error if JSON file is not found', function () {
+      const argv = parser.detailed(['--settings', 'fake.json', '--foo', 'bar'], {
+        alias: {
+          z: 'zoom'
+        },
+        config: ['settings']
+      })
+
+      argv.error.message.should.equal('Invalid JSON config file: fake.json')
+    })
+
+    // see: https://github.com/bcoe/yargs/issues/172
+    it('should not raise an exception if config file is set as default argument value', function () {
+      const argv = parser.detailed([], {
+        default: {
+          config: 'foo.json'
+        },
+        config: ['config']
+      })
+
+      expect(argv.error).to.equal(null)
+    })
+
+    it('should load nested options from config file', function () {
+      const jsonPath = path.resolve(__dirname, './fixtures/nested_config.json')
+      const argv = parser(['--settings', jsonPath, '--nested.foo', 'bar'], {
+        config: ['settings']
+      })
+
+      argv.should.have.property('a', 'a')
+      argv.should.have.property('b', 'b')
+      argv.should.have.property('nested').and.deep.equal({
+        foo: 'bar',
+        bar: 'bar'
+      })
+    })
+
+    it('should use nested value from config file, if argv value is using default value', function () {
+      const jsonPath = path.resolve(__dirname, './fixtures/nested_config.json')
+      const argv = parser(['--settings', jsonPath], {
+        config: ['settings'],
+        default: {
+          'nested.foo': 'banana'
+        }
+      })
+
+      argv.should.have.property('a', 'a')
+      argv.should.have.property('b', 'b')
+      argv.should.have.property('nested').and.deep.equal({
+        foo: 'baz',
+        bar: 'bar'
+      })
+    })
+
+    it('allows a custom parsing function to be provided', function () {
+      const jsPath = path.resolve(__dirname, './fixtures/config.txt')
+      const argv = parser(['--settings', jsPath, '--foo', 'bar'], {
+        config: {
+          settings: function (configPath) {
+            // as an example, parse an environment
+            // variable style config:
+            // FOO=99
+            // BATMAN=grumpy
+            const config = {}
+            const txt = readFileSync(configPath, 'utf-8')
+            txt.split(/\r?\n/).forEach(function (l) {
+              const kv = l.split('=')
+              config[kv[0].toLowerCase()] = kv[1]
+            })
+            return config
+          }
+        }
+      })
+
+      argv.batman.should.equal('grumpy')
+      argv.awesome.should.equal('banana')
+      argv.foo.should.equal('bar')
+    })
+
+    it('allows a custom parsing function to be provided as an alias', function () {
+      const jsPath = path.resolve(__dirname, './fixtures/config.json')
+      const argv = parser(['--settings', jsPath, '--foo', 'bar'], {
+        config: {
+          s: function (configPath) {
+            return JSON.parse(readFileSync(configPath, 'utf-8'))
+          }
+        },
+        alias: {
+          s: ['settings']
+        }
+      })
+
+      argv.should.have.property('herp', 'derp')
+      argv.should.have.property('foo', 'bar')
+    })
+
+    it('outputs an error returned by the parsing function', function () {
+      const argv = parser.detailed(['--settings=./package.json'], {
+        config: {
+          settings: function (configPath) {
+            return Error('someone set us up the bomb')
+          }
+        }
+      })
+
+      argv.error.message.should.equal('someone set us up the bomb')
+    })
+
+    it('outputs an error if thrown by the parsing function', function () {
+      const argv = parser.detailed(['--settings=./package.json'], {
+        config: {
+          settings: function (configPath) {
+            throw Error('someone set us up the bomb')
+          }
+        }
+      })
+
+      argv.error.message.should.equal('someone set us up the bomb')
+    })
+
+    it('should not pollute the prototype', function () {
+      const argv = parser(['--foo', 'bar'], {
+        alias: {
+          z: 'zoom'
+        },
+        default: {
+          settings: jsonPath
+        },
+        config: 'settings'
+      })
+
+      argv.should.have.property('herp', 'derp')
+      argv.should.have.property('zoom', 55)
+      argv.should.have.property('foo').and.deep.equal('bar')
+
+      expect({}.bbb).to.equal(undefined)
+      expect({}.aaa).to.equal(undefined)
+    })
+  })
+})

tsconfig.json

@@ -6,7 +6,7 @@
     "sourceMap": false,
     "target": "es2017",
     "moduleResolution": "node",
-    "module": "es2015"
+    "module": "es2020"
   },  
   "include": [
     "lib/**/*.ts"