Adds support for options to CLI and improves usability

README.md

@@ -42,7 +42,13 @@ Or use the UMD bundle from jsDelivr:
 <script src="https://cdn.jsdelivr.net/npm/liquidjs/dist/liquid.browser.min.js"></script>
 ```
 
-More details, refer to [The Setup Guide][setup].
+Or render directly from CLI using npx:
+
+```bash
+npx liquidjs --template 'Hello, {{ name }}!' --context '{"name": "Snake"}'
+```
+
+For more details, refer to the [Setup Guide][setup].
 
 ## Related Projects
 

bin/liquid.js

@@ -1,24 +1,111 @@
 #!/usr/bin/env node
 
+const fs = require('fs')
 const Liquid = require('..').Liquid
-const contextArg = process.argv.slice(2)[0]
-let context = {}
-
-if (contextArg) {
-  if (contextArg.endsWith('.json')) {
-    const fs = require('fs')
-    context = JSON.parse(fs.readFileSync(contextArg, 'utf8'))
-  } else {
-    context = JSON.parse(contextArg)
+
+// Preserve compatibility by falling back to legacy CLI behavior if:
+// - stdin is redirected (i.e. not connected to a terminal)
+// - there are either no arguments, or only a single argument which does not start with a dash
+// TODO: Remove this fallback for 11.0
+
+if (!process.stdin.isTTY) {
+  if (process.argv.length === 2 || (process.argv.length === 3 && !process.argv[2].startsWith('-'))) {
+    renderLegacy()
+    return
+  }
+}
+
+const { program } = require('commander')
+
+program
+  .name('npx liquidjs')
+  .description('Render a Liquid template')
+  .requiredOption('-t, --template <path | liquid>', 'liquid template to render (as path or inline)') // TODO: Change to argument in 11.0
+  .option('-c, --context <path | json>', 'input context in JSON format (as path or inline; omit to read from stdin)')
+  .option('-o, --output <path>', 'write rendered output to file (omit to write to stdout)')
+  .option('--cache [size]', 'cache previously parsed template structures (default cache size: 1024)')
+  .option('--extname <string>', 'use a default filename extension when resolving partials and layouts')
+  .option('--jekyll-include', 'use jekyll-style include (pass parameters to include variable of current scope)')
+  .option('--js-truthy', 'use JavaScript-style truthiness')
+  .option('--layouts <path...>', 'directories from where to resolve layouts (defaults to --root)')
+  .option('--lenient-if', 'do not throw on undefined variables in conditional expressions (when using --strict-variables)')
+  .option('--no-dynamic-paths', 'always treat file paths for partials and layouts as a literal value')
+  .option('--no-greedy-trim', 'disable greedy matching for --trim* options')
+  .option('--no-relative-paths', 'require absolute file paths for partials and layouts')
+  .option('--ordered-filter-parameters', 'respect parameter order when using filters')
+  .option('--output-delimiter-left <string>', 'left delimiter to use for liquid outputs')
+  .option('--output-delimiter-right <string>', 'right delimiter to use for liquid outputs')
+  .option('--partials <path...>', 'directories from where to resolve partials (defaults to --root)')
+  .option('--preserve-timezones', 'preserve input timezone in date filter')
+  .option('--root <path...>', 'directories from where to resolve partials and layouts (defaults to ".")')
+  .option('--strict-filters', 'throw on undefined filters instead of skipping them')
+  .option('--strict-variables', 'throw on undefined variables instead of rendering them as empty string')
+  .option('--tag-delimiter-left', 'left delimiter to use for liquid tags')
+  .option('--tag-delimiter-right', 'right delimiter to use for liquid tags')
+  .option('--timezone-offset <value>', 'JavaScript timezone name or timezoneOffset value to use in date filter (defaults to local timezone)')
+  .option('--trim-output-left', 'trim whitespace from left of liquid outputs')
+  .option('--trim-output-right', 'trim whitespace from right of liquid outputs')
+  .option('--trim-tag-left', 'trim whitespace from left of liquid tags')
+  .option('--trim-tag-right', 'trim whitespace from right of liquid tags')
+  .showHelpAfterError('Use -h or --help for additional information.')
+  .parse()
+
+const options = program.opts()
+const template = resolvePathOption(options.template)
+const context = resolveContext(options.context)
+const liquidOptions = Object.fromEntries(Object.entries(options).map(([key, value]) => {
+  switch (key) { // Remap options where CLI names differ from property names
+    case 'dynamicPaths': return ['dynamicPartials', value]
+    case 'greedyTrim': return ['greedy', value]
+    case 'relativePaths': return ['relativeReference', value]
+    default: return [key, value]
   }
+}))
+
+const liquid = new Liquid(liquidOptions)
+const output = liquid.parseAndRenderSync(template, context)
+if (options.output) {
+  fs.writeFileSync(options.output, output)
+} else {
+  process.stdout.write(output)
+  process.stdout.write('\n')
 }
 
-let tpl = ''
-process.stdin.on('data', chunk => (tpl += chunk))
-process.stdin.on('end', () => render(tpl))
+function resolveContext (contextOption) {
+  let contextJson = '{}'
+  if (contextOption) {
+    contextJson = resolvePathOption(contextOption)
+  } else if (!process.stdin.isTTY) { // Read context from stdin if not connected to a terminal
+    contextJson = fs.readFileSync(process.stdin.fd, 'utf8')
+  }
+  const context = JSON.parse(contextJson)
+  return context
+}
 
-async function render (tpl) {
+function resolvePathOption (option) {
+  let content = null
+  if (option) {
+    const stat = fs.statSync(option, { throwIfNoEntry: false })
+    if (stat && stat.isFile) {
+      content = fs.readFileSync(option, 'utf8')
+    } else {
+      content = option
+    }
+  }
+  return content
+}
+
+// TODO: Remove for 11.0
+function renderLegacy () {
+  process.stderr.write('Reading template from stdin. This mode will be removed in next major version, use --template option instead.\n')
+  const contextArg = process.argv.slice(2)[0]
+  let context = {}
+  if (contextArg) {
+    const contextJson = resolvePathOption(contextArg)
+    context = JSON.parse(contextJson)
+  }
+  const template = fs.readFileSync(process.stdin.fd, 'utf8')
   const liquid = new Liquid()
-  const html = await liquid.parseAndRender(tpl, context)
-  process.stdout.write(html)
+  const output = liquid.parseAndRenderSync(template, context)
+  process.stdout.write(output)
 }

docs/source/tutorials/setup.md

@@ -53,20 +53,43 @@ Pre-built UMD bundles are also available:
 
 ## LiquidJS in CLI
 
-LiquidJS is also available from CLI:
+LiquidJS can also be used to render a template directly from CLI using `npx`:
 
 ```bash
-echo '{{"hello" | capitalize}}' | npx liquidjs
+npx liquidjs --template '{{"hello" | capitalize}}'
 ```
 
-If you pass a path to a JSON file or a JSON string as the first argument, it will be used as the context for your template.
+You can either pass the template inline (shown above) or you can read it from a file like so:
 
 ```bash
-echo 'Hello, {{ name }}.' | npx liquidjs '{"name": "Snake"}'
+npx liquidjs --template ./some-template.liquid
 ```
 
+You can also pass a context, either inline or from a path or piped through `stdin`. The following three are equivalent:
+
+```bash
+npx liquidjs --template 'Hello, {{ name }}!' --context '{"name": "Snake"}'
+npx liquidjs --template 'Hello, {{ name }}!' --context ./some-context.json
+echo '{"name": "Snake"}' | npx liquidjs --template 'Hello, {{ name }}!'
+```
+
+The rendered output is written to `stdout` by default, but you can also specify an output file (if the file exists, it will be overwritten):
+
+```bash
+npx liquidjs --template '{{"hello" | capitalize}}' --output ./hello.txt
+```
+
+You can also pass a number of options to customize template rendering behavior. For example, the `--js-truthy` option can be used to enable JavaScript truthiness:
+
+```bash
+npx liquidjs --template ./some-template.liquid --js-truthy
+```
+
+Most of the [options available through the JavaScript API][options] are also available from the CLI. For help on available options, use `npx liquidjs --help`.
+
 ## Miscellaneous
 
 A ReactJS demo is also added by [@stevenanthonyrevo](https://github.com/stevenanthonyrevo), see [liquidjs/demo/reactjs/](https://github.com/harttle/liquidjs/blob/master/demo/reactjs/).
 
 [intro]: ./intro-to-liquid.html
+[options]: ./options.md

package.json

@@ -111,6 +111,9 @@
     "typedoc-plugin-markdown": "^2.2.17",
     "typescript": "^4.5.3"
   },
+  "dependencies": {
+    "commander": "^10.0.0"
+  },
   "release": {
     "branch": "master",
     "plugins": [
@@ -160,6 +163,5 @@
       "pre-commit": "npm run check",
       "commit-msg": "commitlint -E HUSKY_GIT_PARAMS"
     }
-  },
-  "dependencies": {}
+  }
 }