Initial commit

LICENSE

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+Copyright 2018 Dylan Baker
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

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+# pj
+
+`pj` is a small command-line utility for inspecting the contents of
+`package.json` files.
+
+## Installation
+
+```console
+$ npm install -g pajamas-cli
+```
+
+## Usage
+
+Invoked without arguments in a directory containing a `package.json`, `pj` will
+simply print the entire object. To inspect a property of the object, pass an
+argument consisting of the path to the property using dot notation. For
+example:
+
+```console
+$ cat package.json
+{
+  "name": "My Package",
+  "version": "0.0.1",
+  "license": "MIT",
+  "keywords": ["node", "json", "cli"]
+  "scripts": {
+    "test": "node test.js"
+  }
+}
+$ pj version
+0.0.1
+$ pj scripts.test
+node test.js
+```
+
+`pj` also supports arrays, also using dot notation:
+
+```console
+$ pj keywords.0
+node
+$ pj keywords.1
+json
+```
+
+## License
+
+`pj` is open source software under the terms of the
+[MIT license] (http://opensource.org/licenses/MIT).

lib.js

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+const traversePath = (object, path) => {
+  const [key, ...rest] = path;
+  if (key === undefined) return object;
+  if (object.hasOwnProperty(key)) {
+    return traversePath(object[key], rest);
+  }
+  return `Property '${key}' does not exist`;
+};
+
+const pj = (contents, path) => {
+  try {
+    const object = JSON.parse(contents);
+    return path.length === 0 ? object : traversePath(object, path);
+  } catch (e) {
+    return new Error('Not a valid JSON file');
+  }
+};
+
+module.exports = {
+  traversePath: traversePath,
+  pj: pj,
+};

package-lock.json

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+{
+  "name": "pajama-cli",
+  "version": "0.1.0",
+  "lockfileVersion": 1
+}

package.json

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+{
+  "name": "pajamas-cli",
+  "version": "0.1.0",
+  "description": "package.json inspector",
+  "bin": {
+    "pj": "pj.js"
+  },
+  "scripts": {
+    "test": "node test.js"
+  },
+  "author": "Dylan Baker <dylanbaker.ct@gmail.com>",
+  "license": "MIT"
+}

pj.js

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+#!/usr/bin/env node
+
+const fs = require('fs');
+const pj = require('./lib').pj;
+
+if (process.argv[2] === '--help') {
+  console.log(`Usage: pj [path]
+
+A path is a string of the form object.property.subproperty representing the
+property to look up. For example, consider the following package.json file:
+
+{
+  "name": "My Package",
+  "version": "0.0.1",
+  "license": "MIT",
+  "keywords": ["node", "json", "cli"]
+  "scripts": {
+    "test": "node test.js"
+  }
+}
+
+You could run \`pj name\`, which would print "My Package", or
+\`pj scripts.test\` which would print "node test.js".`);
+  process.exit();
+}
+
+const path = process.argv.length < 3 ? [] : process.argv[2].split('.');
+
+fs.readFile('./package.json', 'utf-8', (err, contents) => {
+  if (err) {
+    switch (err.code) {
+      case 'ENOENT':
+        console.error('No package.json found in the current directory');
+        process.exit();
+      default:
+        throw err;
+    }
+  }
+  const result = pj(contents, path);
+  switch (result.constructor) {
+    case Error:
+      console.error(result.message);
+      break;
+    default:
+      console.log(result);
+  }
+});

test.js

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+const assert = require('assert');
+const traversePath = require('./lib').traversePath;
+
+const ESCAPE_CODES = {
+  RESET_COLOR: '\x1b[0m',
+  FG_GREEN: '\x1b[32m',
+};
+
+const testCases = [
+  {
+    expected: 1,
+    actual: traversePath({ a: 1 }, ['a']),
+  },
+  {
+    expected: 3,
+    actual: traversePath({ a: { b: { c: 3 } } }, ['a', 'b', 'c']),
+  },
+  {
+    expected: 2,
+    actual: traversePath({ a: [1, 2, 3] }, ['a', 1]),
+  },
+];
+
+testCases.forEach((testCase, i) => {
+  assert.deepEqual(testCase.actual, testCase.expected);
+  [ESCAPE_CODES.FG_GREEN, '.', ESCAPE_CODES.RESET_COLOR].forEach(el =>
+    process.stdout.write(el)
+  );
+});
+
+console.log(ESCAPE_CODES.FG_GREEN, 'OK', ESCAPE_CODES.RESET_COLOR);