initial commit

.babelrc

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+{
+  "presets": ["es2015"]
+}

.gitignore

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+logs
+*.log
+npm-debug.log*
+pids
+*.pid
+*.seed
+lib-cov
+coverage
+.nyc_output
+.grunt
+.lock-wscript
+build/Release
+node_modules
+jspm_packages
+.npm
+.node_repl_history
+*.orig
+.idea
+.DS_Store
+
+# babel output
+index.js

.npmignore

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+logs
+*.log
+npm-debug.log*
+pids
+*.pid
+*.seed
+lib-cov
+coverage
+.nyc_output
+.grunt
+.lock-wscript
+build/Release
+node_modules
+jspm_packages
+.npm
+.node_repl_history
+*.orig
+.idea
+.DS_Store

ISSUE_TEMPLATE.md

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+1) What version of the module is the issue happening on? Does the issue happen on latest version?
+
+2) What platform and Node.js version? (For example Node.js 0.12 on Mac OS X)
+
+3) Sample source code or steps to reproduce
+
+(Write description of your issue here, stack traces from errors and code that reproduces the issue are helpful)
+
+4) If a pull request, do all tests pass?

LICENSE

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+(The MIT License)
+
+Copyright (c) 2016 Bojan D.
+
+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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+# promisify-call
+
+Promisify a function call so users can call a function with a callback or get a promise.
+
+## Installation
+
+`npm install promisify-call`
+
+## Usage
+
+```js
+function _uppercase(param, fn) {
+  setTimeout(() => {
+    return fn(null, param.toUpperCase());
+  }, 50);
+}
+
+function uppercase(param, fn) {
+  return promisifyCall(this, _uppercase, ...arguments);
+}
+
+// now we can call it using callback-style
+uppercase('foo', (err, res) => {
+  console.log(res); // FOO
+});
+
+// OR promise style
+const res = await uppercase('foo');
+console.log(res); // FOO
+```
+
+## API Reference
+
+<a name="promisifyCall"></a>
+
+### promisifyCall(ctx, fn, ...args) ⇒ <code>undefined</code> &#124; <code>\*</code> &#124; <code>Promise</code>
+Promisifies the call to <code>fn</code> if appropriate given the arguments.
+Calls the function <code>fn</code> either using callback style if last argument is a function.
+If last argument is not a function, <code>fn</code> is called returning a promise.
+This lets you create API that can be called in either fashions.
+
+**Kind**: global function  
+**Returns**: <code>undefined</code> &#124; <code>\*</code> &#124; <code>Promise</code> - Promise if promisified  
+
+| Param | Type | Description |
+| --- | --- | --- |
+| ctx | <code>Object</code> | context / this |
+| fn | <code>function</code> | The function to call |
+| ...args | <code>arguments</code> | Arguments |
+
+## License
+
+Copyright 2015 Bojan D.
+
+Licensed under the MIT License.

package.json

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+{
+  "name": "promisify-call",
+  "version": "0.0.0",
+  "description": "Promisify a function call so users can call a function with a callback or get a promise",
+  "main": "index.js",
+  "scripts": {
+    "test": "npm test"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/bojand/promisify-call.git"
+  },
+  "keywords": [
+    "promise",
+    "callback",
+    "promisify"
+  ],
+  "author": {
+    "name": "Bojan Djurkovic <[email protected]>"
+  },
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/bojand/promisify-call/issues"
+  },
+  "homepage": "https://github.com/bojand/promisify-call#readme",
+  "dependencies": {
+    "bluebird": "^3.4.1"
+  },
+  "devDependencies": {
+    "ava": "^0.16.0",
+    "babel-cli": "^6.11.4",
+    "babel-preset-es2015": "^6.13.2",
+    "xo": "^0.16.0"
+  },
+  "scripts": {
+    "test": "npm run dist && ava -v",
+    "dist": "node ./node_modules/babel-cli/bin/babel.js promisify.js --out-file index.js",
+    "docs": "jsdoc2md \"promisify.js\" --heading-depth 3 --template readme.hbs > README.md",
+    "prepublish": "npm run dist"
+  },
+  "ava": {
+    "files": [
+      "test/*.test.js"
+    ]
+  },
+  "directories": {
+    "test": "test"
+  },
+  "xo": {
+    "envs": [
+      "node",
+      "es6",
+      "mocha"
+    ],
+    "esnext": true,
+    "space": true,
+    "rules": {
+      "babel/arrow-parens": 0,
+      "babel/object-curly-spacing": 0,
+      "babel/object-shorthand": 1,
+      "brace-style": [
+        0,
+        "1tbs", {
+          "allowSingleLine": false
+        }
+      ],
+      "no-else-return": 1,
+      "no-unused-vars": 1,
+      "no-prototype-builtins": 0,
+      "import/namespace": 0
+    },
+    "ignores": [
+      "test/**"
+    ]
+  }
+}

promisify.js

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+import Promise from 'bluebird';
+
+/**
+ * Promisifies the call to <code>fn</code> if appropriate given the arguments.
+ * Calls the function <code>fn</code> either using callback style if last argument is a function.
+ * If last argument is not a function, <code>fn</code> is called returning a promise.
+ * This lets you create API that can be called in either fashions.
+ * @param  {Object}   ctx  context / this
+ * @param  {Function} fn   The function to call
+ * @param  {arguments}   args Arguments
+ * @return {undefined|*|Promise}  Promise if promisified
+ */
+function promisifyCall(ctx, fn, ...args) {
+  const lastIndex = args.length - 1;
+  const lastArg = args && args.length > 0 ? args[lastIndex] : null;
+  const cb = typeof lastArg === 'function' ? lastArg : null;
+
+  if (cb) {
+    return fn.apply(ctx, args);
+  }
+
+  return Promise.fromCallback(callback => {
+    args.push(callback);
+    fn.apply(ctx, args);
+  });
+}
+
+module.exports = promisifyCall;

readme.hbs

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+# promisify-call
+
+Promisify a function call so users can call a function with a callback or get a promise.
+
+## Installation
+
+`npm install promisify-call`
+
+## Usage
+
+```js
+function _uppercase(param, fn) {
+  setTimeout(() => {
+    return fn(null, param.toUpperCase());
+  }, 50);
+}
+
+function uppercase(param, fn) {
+  return promisifyCall(this, _uppercase, ...arguments);
+}
+
+// now we can call it using callback-style
+uppercase('foo', (err, res) => {
+  console.log(res); // FOO
+});
+
+// OR promise style
+const res = await uppercase('foo');
+console.log(res); // FOO
+```
+
+## API Reference
+
+{{>all-docs~}}
+
+## License
+
+Copyright 2015 Bojan D.
+
+Licensed under the MIT License.

test/promisify.test.js

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+import test from 'ava';
+
+import promisifyCall from '../';
+
+function testFn(param, fn) {
+  setTimeout(() => {
+    if (param.toLowerCase() === 'error') {
+      return fn(new Error(param));
+    }
+    return fn(null, param.toUpperCase());
+  }, 50);
+}
+
+function uppercase(param, fn) {
+  return promisifyCall(this, testFn, ...arguments);
+}
+
+test.cb('should properly return success value - callback', t => {
+  uppercase('foo', (err, res) => {
+    t.ifError(err);
+    t.is(res, 'FOO');
+    t.end();
+  });
+});
+
+test.cb('should properly return errpr value - callback', t => {
+  uppercase('error', (err, res) => {
+    t.truthy(err);
+    t.falsy(res);
+    t.end();
+  });
+});
+
+test.cb('should properly return success value - promised using then()', t => {
+  uppercase('foo').then(res => {
+    t.is(res, 'FOO');
+    t.end();
+  });
+});
+
+test.cb('should properly return errpr value - promised using then()', t => {
+  uppercase('error').then(res => {
+    t.falsy(res);
+  }).catch(err => {
+    t.truthy(err);
+    t.end();
+  });
+});
+
+test('should properly return success value - promised', async t => {
+  t.plan(1);
+  const res = await uppercase('foo');
+  t.is(res, 'FOO');
+});
+
+test('should properly return errpr value - promised', t => {
+  t.throws(uppercase('error'));
+});