feat: Add CLI tool (#523)

Skip CI tests for Node.js < 20

README.md

@@ -33,6 +33,8 @@ npm install yaml
 The API provided by `yaml` has three layers, depending on how deep you need to go: [Parse & Stringify](https://eemeli.org/yaml/#parse-amp-stringify), [Documents](https://eemeli.org/yaml/#documents), and the underlying [Lexer/Parser/Composer](https://eemeli.org/yaml/#parsing-yaml).
 The first has the simplest API and "just works", the second gets you all the bells and whistles supported by the library along with a decent [AST](https://eemeli.org/yaml/#content-nodes), and the third lets you get progressively closer to YAML source, if that's your thing.
 
+A [command-line tool](https://eemeli.org/yaml/#command-line-tool) is also included.
+
 ```js
 import { parse, stringify } from 'yaml'
 // or
@@ -55,26 +57,26 @@ const YAML = require('yaml')
   - [`#directives`](https://eemeli.org/yaml/#stream-directives)
   - [`#errors`](https://eemeli.org/yaml/#errors)
   - [`#warnings`](https://eemeli.org/yaml/#errors)
-- [`isDocument(foo): boolean`](https://eemeli.org/yaml/#identifying-nodes)
+- [`isDocument(foo): boolean`](https://eemeli.org/yaml/#identifying-node-types)
 - [`parseAllDocuments(str, options?): Document[]`](https://eemeli.org/yaml/#parsing-documents)
 - [`parseDocument(str, options?): Document`](https://eemeli.org/yaml/#parsing-documents)
 
 ### Content Nodes
 
-- [`isAlias(foo): boolean`](https://eemeli.org/yaml/#identifying-nodes)
-- [`isCollection(foo): boolean`](https://eemeli.org/yaml/#identifying-nodes)
-- [`isMap(foo): boolean`](https://eemeli.org/yaml/#identifying-nodes)
-- [`isNode(foo): boolean`](https://eemeli.org/yaml/#identifying-nodes)
-- [`isPair(foo): boolean`](https://eemeli.org/yaml/#identifying-nodes)
-- [`isScalar(foo): boolean`](https://eemeli.org/yaml/#identifying-nodes)
-- [`isSeq(foo): boolean`](https://eemeli.org/yaml/#identifying-nodes)
+- [`isAlias(foo): boolean`](https://eemeli.org/yaml/#identifying-node-types)
+- [`isCollection(foo): boolean`](https://eemeli.org/yaml/#identifying-node-types)
+- [`isMap(foo): boolean`](https://eemeli.org/yaml/#identifying-node-types)
+- [`isNode(foo): boolean`](https://eemeli.org/yaml/#identifying-node-types)
+- [`isPair(foo): boolean`](https://eemeli.org/yaml/#identifying-node-types)
+- [`isScalar(foo): boolean`](https://eemeli.org/yaml/#identifying-node-types)
+- [`isSeq(foo): boolean`](https://eemeli.org/yaml/#identifying-node-types)
 - [`new Scalar(value)`](https://eemeli.org/yaml/#scalar-values)
 - [`new YAMLMap()`](https://eemeli.org/yaml/#collections)
 - [`new YAMLSeq()`](https://eemeli.org/yaml/#collections)
 - [`doc.createAlias(node, name?): Alias`](https://eemeli.org/yaml/#working-with-anchors)
 - [`doc.createNode(value, options?): Node`](https://eemeli.org/yaml/#creating-nodes)
 - [`doc.createPair(key, value): Pair`](https://eemeli.org/yaml/#creating-nodes)
-- [`visit(node, visitor)`](https://eemeli.org/yaml/#modifying-nodes)
+- [`visit(node, visitor)`](https://eemeli.org/yaml/#finding-and-modifying-nodes)
 
 ### Parsing YAML
 

bin.mjs

@@ -0,0 +1,11 @@
+#!/usr/bin/env node
+
+import { UserError, cli, help } from './dist/cli.mjs'
+
+cli(process.stdin, error => {
+  if (error instanceof UserError) {
+    if (error.code === UserError.ARGS) console.error(`${help}\n`)
+    console.error(error.message)
+    process.exitCode = error.code
+  } else if (error) throw error
+})

config/jest.config.js

@@ -1,6 +1,6 @@
 let moduleNameMapper
 const transform = {
-  '[/\\\\]tests[/\\\\].*\\.(js|ts)$': [
+  '[/\\\\]tests[/\\\\].*\\.(m?js|ts)$': [
     'babel-jest',
     { configFile: './config/babel.config.js' }
   ]
@@ -12,16 +12,22 @@ switch (process.env.npm_lifecycle_event) {
     console.log('Testing build output from dist/')
     moduleNameMapper = {
       '^yaml$': '<rootDir>/dist/index.js',
+      '^yaml/cli$': '<rootDir>/dist/cli.mjs',
       '^yaml/util$': '<rootDir>/dist/util.js',
       '^../src/test-events$': '<rootDir>/dist/test-events.js'
     }
+    transform['[/\\\\]dist[/\\\\].*\\.mjs$'] = [
+      'babel-jest',
+      { configFile: './config/babel.config.js' }
+    ]
     break
 
   case 'test':
   default:
     process.env.TRACE_LEVEL = 'log'
     moduleNameMapper = {
       '^yaml$': '<rootDir>/src/index.ts',
+      '^yaml/cli$': '<rootDir>/src/cli.ts',
       '^yaml/util$': '<rootDir>/src/util.ts'
     }
     transform['[/\\\\]src[/\\\\].*\\.ts$'] = [

config/rollup.node-config.mjs

@@ -1,17 +1,26 @@
+import { chmod, stat } from 'node:fs/promises'
 import typescript from '@rollup/plugin-typescript'
 
-export default {
-  input: {
-    index: 'src/index.ts',
-    'test-events': 'src/test-events.ts',
-    util: 'src/util.ts'
+export default [
+  {
+    input: {
+      index: 'src/index.ts',
+      'test-events': 'src/test-events.ts',
+      util: 'src/util.ts'
+    },
+    output: {
+      dir: 'dist',
+      format: 'cjs',
+      esModule: false,
+      preserveModules: true
+    },
+    plugins: [typescript()],
+    treeshake: { moduleSideEffects: false, propertyReadSideEffects: false }
   },
-  output: {
-    dir: 'dist',
-    format: 'cjs',
-    esModule: false,
-    preserveModules: true
-  },
-  plugins: [typescript()],
-  treeshake: { moduleSideEffects: false, propertyReadSideEffects: false }
-}
+  {
+    input: 'src/cli.ts',
+    output: { file: 'dist/cli.mjs' },
+    external: () => true,
+    plugins: [typescript()]
+  }
+]

docs/01_intro.md

@@ -43,6 +43,8 @@ This requirement may be updated between minor versions of the library.
 The API provided by `yaml` has three layers, depending on how deep you need to go: [Parse & Stringify](#parse-amp-stringify), [Documents](#documents), and the underlying [Lexer/Parser/Composer](#parsing-yaml).
 The first has the simplest API and "just works", the second gets you all the bells and whistles supported by the library along with a decent [AST](#content-nodes), and the third lets you get progressively closer to YAML source, if that's your thing.
 
+A [command-line tool](#command-line-tool) is also included.
+
 <h3>Parse & Stringify</h3>
 
 ```js

docs/09_cli.md

@@ -0,0 +1,26 @@
+# Command-line Tool
+
+Available as `npx yaml` or `npm exec yaml`:
+
+<pre id="cli-help" style="float: none">
+yaml: A command-line YAML processor and inspector
+
+Reads stdin and writes output to stdout and errors & warnings to stderr.
+
+Usage:
+  yaml          Process a YAML stream, outputting it as YAML
+  yaml cst      Parse the CST of a YAML stream
+  yaml lex      Parse the lexical tokens of a YAML stream
+  yaml valid    Validate a YAML stream, returning 0 on success
+
+Options:
+  --help, -h    Show this message.
+  --json, -j    Output JSON.
+
+Additional options for bare "yaml" command:
+  --doc, -d     Output pretty-printed JS Document objects.
+  --single, -1  Require the input to consist of a single YAML document.
+  --strict, -s  Stop on errors.
+  --visit, -v   Apply a visitor to each document (requires a path to import)
+  --yaml 1.1    Set the YAML version. (default: 1.2)
+</pre>

docs/index.html.md

@@ -15,7 +15,8 @@ includes:
   - 06_custom_tags
   - 07_parsing_yaml
   - 08_errors
-  - 09_yaml_syntax
+  - 09_cli
+  - 10_yaml_syntax
 
 search: true
 ---

docs/prepare-docs.mjs

@@ -1,12 +1,30 @@
 #!/usr/bin/env node
 
-import { lstat, mkdir, readdir, readFile, symlink, rm } from 'node:fs/promises'
+import {
+  lstat,
+  mkdir,
+  readdir,
+  readFile,
+  symlink,
+  rm,
+  writeFile
+} from 'node:fs/promises'
 import { resolve } from 'node:path'
+import { help } from '../dist/cli.mjs'
 import { parseAllDocuments } from '../dist/index.js'
 
 const source = 'docs'
 const target = 'docs-slate/source'
 
+// Update CLI help
+const cli = resolve(source, '09_cli.md')
+const docs = await readFile(cli, 'utf-8')
+const update = docs.replace(
+  /(<pre id="cli-help".*?>).*?(<\/pre>)/s,
+  '$1\n' + help + '\n$2'
+)
+if (update !== docs) await writeFile(cli, update)
+
 // Create symlink for index.html.md
 const indexSource = resolve(source, 'index.html.md')
 const indexTarget = resolve(target, 'index.html.md')

package.json

@@ -18,6 +18,7 @@
   ],
   "type": "commonjs",
   "main": "./dist/index.js",
+  "bin": "./bin.mjs",
   "browser": {
     "./dist/index.js": "./browser/index.js",
     "./dist/util.js": "./browser/dist/util.js",