adds an option to accept data directly from stdin (#59)

* feat: accept data from stdin

Closes #54

* docs: update README to reflect new usage options

README.md

@@ -13,9 +13,13 @@ Usage:
   -h, --help                 output usage information
   -v, --version              output the version number
   -o, --output <directory>   Directory to output rendered templates, defaults to cwd
-  -P, --partial <glob>...    Register a partial* (use as many of these as you want)
-  -H, --helper <glob>...     Register a helper* (use as many of these as you want)
-  -D, --data <glob|json>...  Parse some data*
+  -e, --extension            Output extension of generated files, defaults to html
+  -s, --stdout               Output to standard output
+  -i, --stdin                Receive data directly from stdin
+  -P, --partial <glob>...    Register a partial (use as many of these as you want)
+  -H, --helper <glob>...     Register a helper (use as many of these as you want)
+
+  -D, --data <glob|json>...  Parse some data
 
 Examples:
 

package.json

@@ -22,11 +22,13 @@
     "prepublish": "babel src -d lib",
     "pretest": "npm run lint",
     "semantic-release": "semantic-release pre && npm publish && semantic-release post",
-    "test": "npm run test:run:1 && npm run test:verify:1 && npm run test:run:2 && npm run test:verify:2",
+    "test": "npm run test:run:1 && npm run test:verify:1 && npm run test:run:2 && npm run test:verify:2 && npm run test:run:3 && npm run test:verify:3",
     "test:run:1": "node . -H handlebars-helper-br -D ./test/data.json -o test test/test-1.hbs",
     "test:verify:1": "diff test/test-1.html test/verify-1.html",
     "test:run:2": "node . -s -H handlebars-helper-br -D ./test/data.json test/test-1.hbs > test/test-2.html",
     "test:verify:2": "diff test/test-2.html test/verify-1.html",
+    "test:run:3": "cat ./test/data.json | node . -s -H handlebars-helper-br --stdin test/test-1.hbs > test/test-3.html",
+    "test:verify:3": "diff test/test-3.html test/verify-1.html",
     "watch": "npm run prepublish -- -w"
   },
   "config": {
@@ -55,6 +57,7 @@
     "babel-runtime": "^5.8.34",
     "debug": "^2.2.0",
     "fs-promise": "^0.3.1",
+    "get-stdin": "^8.0.0",
     "glob-promise": "^1.0.4",
     "handlebars": "^4.0.5",
     "lodash.merge": "^3.3.2",

src/index.js

@@ -8,6 +8,7 @@ import resolveNode from 'resolve';
 import { readFile, writeFile } from 'fs-promise';
 import merge from 'lodash.merge';
 import mkdirp from 'mkdirp-then';
+import getStdin from 'get-stdin';
 const debug = require('debug')('hbs');
 function resolve(file, options) {
   return new Promise((resolvePromise, reject) => resolveNode(file, options, (error, path) => {
@@ -86,6 +87,16 @@ export async function addObjectsToData(objects) {
   return merge({}, ...dataSets.concat(fileContents));
 }
 
+export async function getStdinData() {
+  const text = await getStdin();
+  try {
+    debug(`Attempting to parse ${text} as JSON`);
+    return JSON.parse(text);
+  } catch (error) {
+    throw new Error(`stdin cannot be parsed as JSON`);
+  }
+}
+
 export async function renderHandlebarsTemplate(
   files, outputDirectory = process.cwd(),
   outputExtension = 'html', data = {}, stdout = false) {
@@ -117,13 +128,15 @@ if (require.main === module) {
       'version',
       'help',
       'stdout',
+      'stdin',
     ],
     alias: {
       'v': 'version',
       'h': 'help',
       'o': 'output',
       'e': 'extension',
       's': 'stdout',
+      'i': 'stdin',
       'D': 'data',
       'P': 'partial',
       'H': 'helper',
@@ -144,6 +157,7 @@ if (require.main === module) {
       -o, --output <directory>   Directory to output rendered templates, defaults to cwd
       -e, --extension            Output extension of generated files, defaults to html
       -s, --stdout               Output to standard output
+      -i, --stdin                Receive data directly from stdin
       -P, --partial <glob>...    Register a partial (use as many of these as you want)
       -H, --helper <glob>...     Register a helper (use as many of these as you want)
 
@@ -170,6 +184,10 @@ if (require.main === module) {
       debug('Setting up data', options.data);
       setup.push(addObjectsToData(options.data).then((result) => data = result));
     }
+    if (options.stdin) {
+      debug('Setting up stdin', options.stdin);
+      setup.push(getStdinData().then((stdinData) => data = stdinData));
+    }
     Promise.all(setup)
       .then(() => expandGlobList(options._))
       .then((files) => renderHandlebarsTemplate(files, options.output, options.extension, data, options.stdout))