Node.js, require all modules in folder and use loaded module directly

Node.js, require all modules in folder and use loaded module directly - javascript

In MyModule folder, I have this two JS files.
SayHello.js
module.exports.SayHello = function() {
return('Hello !');
}
SayByeBye.js
module.exports.SayByeBye = function() {
return('Bye Bye!');
}
In Node.js, I want to require all files in MyModule folder and call function SayHello & SayByeBye directly something like:
require(./MyModule)
console.log(SayHello());
console.log(SayByeBye());
EDIT:
With answer of #Yanick Rochon,I do this :
> ./app/my-module/index.js
global.SayHello = require('./my-module/SayHello').SayHello;
global.SayByeBye = require('./my-module/SayByeBye').SayByeBye;
> ./app/my-module/say-hello.js
module.exports.SayHello = function() {
return('Hello !');
};
> ./app/my-module/say-byebye.js
module.exports.SayByeBye = function() {
return('Bye Bye !');
};
> ./app/main.js
require('./my-module');
console.log(SayHello());
console.log(SayByeBye());
There's a section about global objects in the node documentation.
However, globals should be used with care. By adding modules to the global space I reduce testability and encapsulation. But in this case, I think using this method is acceptable.

First thing first...
I believe you are mistaking Node.js with PHP or .Net, in the sense that you don't "import" into the current module what is exported in other modules. Not unless you manually do it anyway. For example, when you call
require('./my-module');
(Note that I renamed your MyModule into Node.js naming convention.)
You don't load things into the current context; you just load the script and don't assign it to anything. To access what my-module exposes, you need to assign it, or use it directly. For example :
require('./my-module').someFunction();
or
var myModule = require('./my-module');
myModule.someFunction();
Modules are not namespaces, but JavaScript objects that exposes public properties outside of their own contexts (i.e. using module.exports = ...)
Answer
You have two most popular ways to accomplish this :
Solution 1
Create an index.json file inside your folder where you want to load all of your scripts. The returned JSON object should be all the modules to load automatically :
> ./app/index.json
[
"say-hello.js",
"say-goodbye.js"
]
You should also consider having all your files API compatible :
> ./app/say-hello.js
module.exports = function sayHello() {
return 'Hello !';
};
> ./app/say-goodbye.js
module.exports.sayGoodbye = function () {
return 'Goodbye !';
};
Then load and execute everything like this :
var path = require('path');
var basePath = './app/';
var files = require(basePath);
var mods = files.forEach(function (loaded, file) {
var mod = require(path.join(basePath, file));
// mod is a function with a name, so use it!
if (mod instanceof Function) {
loaded[mod.name] = mod;
} else {
Object.keys(mod).forEach(function (property) {
loaded[property] = mod.property;
});
}
}, {});
mods.sayHello();
mods.sayGoodbye();
Solution 2
Read all .js files inside your folder and import them. I highly recommend you use glob for this.
var glob = require("glob")
var path = require('path');
var basePath = './app/';
var mods = glob.sync(path.join(basePath, '*.js')).reduce(function (loaded, file) {
var mod = require(file);
// mod is a function with a name, so use it!
if (mod instanceof Function) {
loaded[mod.name] = mod;
} else {
Object.keys(mod).forEach(function (property) {
loaded[property] = mod.property;
});
}
return loaded;
}, {});
mods.sayHello();
mods.sayGoodbye();
Note on the difference between module.exports and exports
Typically module.exports === exports, but it is recommended to use module.exports for the following reason
exports = function Foo() { } // will not do anything
module.exports = function Foo() { } // but this will do what you expect
// however these two lines produce the same result
exports.foo = 'Bar';
module.exports.foo = 'Bar';
For this reason, module.exports is recommended in all cases.

It's not perfect, but something like this should help you accomplish this:
var fs = require('fs');
var path = require('path');
var files = fs.readdirSync(__dirname);
var ownFilename = __filename.substr(__filename.lastIndexOf(path.delimiter) + 1);
var modules = {};
for (var i = 0; i < files.length; i++) {
var filename = files[i];
if (filename.substr(-3) === '.js' && filename !== ownFilename) {
modules[filename.slice(0, -3)] = require('./' + filename);
}
}
console.log(modules.SayByeBye());
console.log(modules.SayHello());

Related

Is it possible to launch js files with different permissions using nodejs/npm?

I want to launch a js file in a js file with different permission. Just like this:
main.js (which gets started)
config = JSON.parse(require("./config.json")) // <- should be possible
console.log(config.authkey) // <- should be possible
require("./randomJSFile.js").run()
randomJSFile.js (which will be executed by main.js)
exports.run = () => {
let config = JSON.parse(require("./config.json") // <--- this should not be possible, only the main.js file should have access to the config.json file
console.log(config.authkey) // should not be possible
}
Does anyone know how to do something like that?

Based on a snippet from this question here you could possibly override the require function to check for the filename, something like this:
const Module = require('module');
const originalRequire = Module.prototype.require;
Module.prototype.require = function() {
if (!arguments.length || typeof arguments[0] !== 'string') return {};
if (arguments[0].includes('config.json')) return {};
return originalRequire.apply(this, arguments);
};
And then perform this override after you've already required the config in your main file, so you don't accidentally block yourself

Exporting two module under same directory not working when requiring from same file

I have two js file under same directory:
main/file1.js and main/file2.js. Then I call it under my test folder test/files.js
If I have this in my file1.js:
function file1(){
let result = "a";
return result;
}
module.exports = file1
Then my file2.js:
let v = "c" //this is the error that make file2 undefined. scope issue.
function file2(){
let result = "b";
return v;
}
module.exports = file2
Then in my test file I am requiring both files. file1's steps function works fine but the file2's steps2 is undefined. Any thought?
const assert = require('assert');
const steps = require('../main/steps');
const steps2 = require('../main/steps2');
describe('steps', function(){
it('make steps', function(){
assert.equal(file1(), 'a');
});
it('make steps2', function(){
assert.equal(file2(), 'b');
});
})

You're requiring the function name when you should be requiring the file name. Your requires should look something like this:
const steps = require('../main/file1');
const steps2 = require('../main/file2');

How to create a Node.js module from Asynchronous Function response?

This problem is in regards the creation of a Node module that depends on a async function to return the content. For instance, "src/index.js" is the following:
GOAL
The module A, implemented from "src/index" must be resolved and must not depend on promises, or anything else... It will just return a JSON object of computed values.
var a = require("./src/index");
// should be resolved already.
console.log(a.APP_NAME)
src/index.js
"use strict";
var CoreClass = require("./core-class");
var coreInstance = new CoreClass();
coreInstance.toJson(function(err, coreData) {
if (err) {
console.log("Error while loading " + __filename);
console.log(err);
return;
}
console.log(coreData);
// Export the data from the core.
module.exports = coreData;
});
src/core-class.js
The implementation of the method "toJson()", defined in the class in the file "src/core-class.js" is as follows:
/**
* #return {string} Overriding the toStrng to return the object properties.
*/
ISPCore.prototype.toJson = function toJson(callback) {
var result = {
// From package.json
APP_NAME: this.appPackageJson.name.trim(),
APP_VERSION: this.appPackageJson.version.trim(),
APP_CONFIG_DIR: this.APP_DIR + "/config",
APP_DOCS_DIR: this.APP_DIR + "/docs",
APP_TESTS_DIR: this.APP_DIR + "/tests",
};
// TODO: Remove this when we have a registry
if (!this.pom) {
// Let's verify if there's a pom.xml file in the roort APP_DIR
var _this = this;
this.APP_POM_PATH = this.APP_DIR + "/pom.xml";
// Check first to see if the file exists
fs.stat(this.APP_POM_PATH, function(err, fileStats) {
// The file does not exist, so we can continue with the current result.
if (err) {
return callback(null, result);
}
_this._loadPomXmlSettings(function pomXmlCallback(err, pomObject) {
if (err) {
return callback(err);
}
_this.pom = pomObject;
// Update the result with the pom information
result.POM_GROUPID = _this.pom.groupid || "undefined";
result.POM_ARTIFACTID = _this.pom.artifactid || "undefined";
result.POM_VERSION = _this.pom.version || "undefined";
// Callback with the updated version.
return callback(null, result);
});
});
} else {
result.POM_GROUPID = this.pom.groupid || "undefined";
result.POM_ARTIFACTID = this.pom.artifactId || "undefined";
result.POM_VERSION = this.pom.version || "undefined";
// Return just what's been collected so far, including the pom.
return callback(null, result);
}
};
Test class
Requiring this and trying to use the library just returns an empty object. Here's the test class...
// describing the method to get the instance.
describe("require(sp-core) with pom.xml", function() {
var core = null;
before(function(done) {
// Copy the fixture pom.xml to the APP_DIR
fs.writeFileSync(__dirname + "/../pom.xml", fs.readFileSync(__dirname + "/fixture/pom.xml"));
// Load the library after the creation of the pom
core = require("../src/");
console.log("TEST AFTER CORE");
console.log(core);
done();
});
after(function(done) {
// Delete the pom.xml from the path
fs.unlinkSync(__dirname + "/../pom.xml");
done();
});
it("should load the properties with pom properties", function(done) {
expect(core).to.be.an("object");
console.log("Loaded pom.xml metadata");
console.log(core);
expect(core.POM_ARTIFACTID).to.exist;
expect(core.POM_VERSION).to.exist;
done();
});
});
Execution of the tests
However, after a while, the output from the library shows up in the console.
SPCore with pom.xml
require(sp-core) with pom.xml
TEST AFTER CORE
{}
Loaded pom.xml metadata
{}
1) should load the properties with pom properties
{ APP_NAME: 'sp-core',
APP_VERSION: '0.3.5',
ENV: 'development',
NODE_ENV: 'development',
IS_PROD: false,
APP_DIR: '/home/mdesales/dev/isp/sp-core',
APP_CONFIG_DIR: '/home/mdesales/dev/isp/sp-core/config',
APP_DOCS_DIR: '/home/mdesales/dev/isp/sp-core/docs',
APP_TESTS_DIR: '/home/mdesales/dev/isp/sp-core/tests',
POM_GROUPID: 'com.mycompany',
POM_ARTIFACTID: 'my-service',
POM_VERSION: '1.0.15-SNAPSHOT' }
0 passing (142ms)
1 failing
1) SPCore with pom.xml require(sp-core) with pom.xml should load the properties with pom properties:
AssertionError: expected undefined to exist
How to properly create a module that depends on an Async call?
I'm sure this is due to the asynchronous call, but I was thinking that the module would not return {}, but wait until the callback returns.
I tried using:
Async.waterfall
Deasync (does not work)
Async.waterfall attempt
"use strict";
var async = require("async");
var CoreClass = require("./core-class");
var coreInstance = new CoreClass();
async.waterfall([
function(cb) {
coreInstance.toJson(cb);
},
function(coreData) {
console.log(coreData);
module.exports = coreData;
}
]);
Please please help!

Following the comments, I revisited the attempt of using "deasync" module, and it WORKS! YES WE CAN! Cheating with the hack of "deasync" :D
Runnable instance
The runnable solution is at http://code.runnable.com/VbCksvKBUC4xu3rd/demo-that-an-async-method-can-be-returned-before-a-module-exports-is-resolved-for-node-js-deasync-pom-parser-and-stackoverflow-31577688
Type "npm test" in the terminal box and hit "ENTER" (always works).
Just click in the "Run" button to see the execution of the code. All the source code is available. (Sometimes the container gets corrupted and the test fails).
Solution
Here's the implementation of the "GOAL" module.
/** #module Default Settings */
"use strict";
var CoreClass = require("./core-class");
var merge = require("merge");
var deasync = require("deasync");
// Core properties needed.
var coreInstance = new CoreClass();
var coreProperties = coreInstance.toJson();
// Pom properties temporary support, deasync the async call
var loadPom = deasync(coreInstance.loadPomXmlSettings);
var pomObject = loadPom(coreProperties.APP_POM_PATH);
// Merge them all.
var allProperties = merge(coreProperties, pomObject);
module.exports = allProperties;
With that, all the code is returned as expected for the module.exports!

How do I require() from the console using webpack?

How do I require() / import modules from the console? For example, say I've installed the ImmutableJS npm, I'd like to be able to use functions from the module while I'm working in the console.

Here's another more generic way of doing this.
Requiring a module by ID
The current version of WebPack exposes webpackJsonp(...), which can be used to require a module by ID:
function _requireById(id) {
return webpackJsonp([], null, [id]);
}
or in TypeScript
window['_requireById'] =
(id: number): any => window['webpackJsonp'];([], null, [id]);
The ID is visible at the top of the module in the bundled file or in the footer of the original source file served via source maps.
Requiring a module by name
Requiring a module by name is much trickier, as WebPack doesn't appear to keep any reference to the module path once it has processed all the sources. But the following code seems to do the trick in lot of the cases:
/**
* Returns a promise that resolves to the result of a case-sensitive search
* for a module or one of its exports. `makeGlobal` can be set to true
* or to the name of the window property it should be saved as.
* Example usage:
* _requireByName('jQuery', '$');
* _requireByName('Observable', true)´;
*/
window['_requireByName'] =
(name: string, makeGlobal?: (string|boolean)): Promise<any> =>
getAllModules()
.then((modules) => {
let returnMember;
let module = _.find<any, any>(modules, (module) => {
if (_.isObject(module.exports) && name in module.exports) {
returnMember = true;
return true;
} else if (_.isFunction(module.exports) &&
module.exports.name === name) {
return true;
}
});
if (module) {
module = returnMember ? module.exports[name] : module.exports;
if (makeGlobal) {
const moduleName = makeGlobal === true ? name : makeGlobal as string;
window[moduleName] = module;
console.log(`Module or module export saved as 'window.${moduleName}':`,
module);
} else {
console.log(`Module or module export 'name' found:`, module);
}
return module;
}
console.warn(`Module or module export '${name}'' could not be found`);
return null;
});
// Returns promise that resolves to all installed modules
function getAllModules() {
return new Promise((resolve) => {
const id = _.uniqueId('fakeModule_');
window['webpackJsonp'](
[],
{[id]: function(module, exports, __webpack_require__) {
resolve(__webpack_require__.c);
}},
[id]
);
});
}
This is quick first shot at this, so it's all up for improvement!

Including this in a module will allow require([modules], function) to be used from a browser
window['require'] = function(modules, callback) {
var modulesToRequire = modules.forEach(function(module) {
switch(module) {
case 'immutable': return require('immutable');
case 'jquery': return require('jquery');
}
})
callback.apply(this, modulesToRequire);
}
Example Usage:
require(['jquery', 'immutable'], function($, immutable) {
// immutable and $ are defined here
});
Note: Each switch-statement option should either be something this module already requires, or provided by ProvidePlugin
Sources:
Based on this answer, which can be used to add an entire folder.
Alternative method from Webpack Docs - which allows something like require.yourModule.function()

I found a way that works, for both WebPack 1 and 2. (as long as the source is non-minified)
Repo: https://github.com/Venryx/webpack-runtime-require
Install
npm install --save webpack-runtime-require
Usage
First, require the module at least once.
import "webpack-runtime-require";
It will then add a Require() function to the window object, for use in the console, or anywhere in your code.
Then just use it, like so:
let React = Require("react");
console.log("Retrieved React.Component: " + React.Component);
It's not very pretty (it uses regexes to search the module wrapper functions) or fast (takes ~50ms the first call, and ~0ms after), but both of these are perfectly fine if it's just for hack-testing in the console.
Technique
The below is a trimmed version of the source to show how it works. (see the repo for the full/latest)
var WebpackData;
webpackJsonp([],
{123456: function(module, exports, __webpack_require__) {
WebpackData = __webpack_require__;
}},
[123456]
);
var allModulesText;
var moduleIDs = {};
function GetIDForModule(name) {
if (allModulesText == null) {
let moduleWrapperFuncs = Object.keys(WebpackData.m).map(moduleID=>WebpackData.m[moduleID]);
allModulesText = moduleWrapperFuncs.map(a=>a.toString()).join("\n\n\n");
// these are examples of before and after webpack's transformation: (which the regex below finds the var-name of)
// require("react-redux-firebase") => var _reactReduxFirebase = __webpack_require__(100);
// require("./Source/MyComponent") => var _MyComponent = __webpack_require__(200);
let regex = /var ([a-zA-Z_]+) = __webpack_require__\(([0-9]+)\)/g;
let matches = [];
let match;
while (match = regex.exec(allModulesText))
matches.push(match);
for (let [_, varName, id] of matches) {
// these are examples of before and after the below regex's transformation:
// _reactReduxFirebase => react-redux-firebase
// _MyComponent => my-component
// _MyComponent_New => my-component-new
// _JSONHelper => json-helper
let moduleName = varName
.replace(/^_/g, "") // remove starting "_"
.replace(new RegExp( // convert chars where:
"([^_])" // is preceded by a non-underscore char
+ "[A-Z]" // is a capital-letter
+ "([^A-Z_])", // is followed by a non-capital-letter, non-underscore char
"g"),
str=>str[0] + "-" + str[1] + str[2] // to: "-" + char
)
.replace(/_/g, "-") // convert all "_" to "-"
.toLowerCase(); // convert all letters to lowercase
moduleIDs[moduleName] = parseInt(id);
}
}
return moduleIDs[name];
}
function Require(name) {
let id = GetIDForModule(name);
return WebpackData.c[id].exports;
}

Being able to use require modules in the console is handy for debugging and code analysis. #psimyn's answer is very specific so you aren't likely to maintain that function with all the modules you might need.
When I need one of my own modules for this purpose, I assign a window property to it so I can get at it e.g window.mymodule = whatever_im_exporting;. I use the same trick to expose a system module if I want to play with it e.g:
myservice.js:
let $ = require('jquery');
let myService = {};
// local functions service props etc...
module.exports = myService;
// todo: remove these window prop assignments when done playing in console
window.$ = $;
window.myService = myService;
It is still a bit of a pain, but digging into the bundles, I can't see any way to conveniently map over modules.

The answer from #Rene Hamburger is good but unfortunately doesn't work anymore (at least with my webpack version). So I updated it:
function getWebpackInternals() {
return new Promise((resolve) => {
const id = 'fakeId' + Math.random();
window['webpackJsonp'].push(["web", {
[id]: function(module, __webpack_exports__, __webpack_require__) {
resolve([module, __webpack_exports__, __webpack_require__])
}
},[[id]]]);
});
}
function getModuleByExportName(moduleName) {
return getWebpackInternals().then(([_, __webpack_exports__, __webpack_require__]) => {
const modules = __webpack_require__.c;
const moduleFound = Object.values(modules).find(module => {
if (module && module.exports && module.exports[moduleName]) return true;
});
if (!moduleFound) {
console.log('couldnt find module ' + moduleName);
return;
}
return moduleFound.exports[moduleName];
})
}
getModuleByExportName('ExportedClassOfModule');

expose-loader is, in my opinion, a more elegant solution:
require("expose-loader?libraryName!./file.js");
// Exposes the exports for file.js to the global context on property "libraryName".
// In web browsers, window.libraryName is then available.

Adding the below code to one of your modules will allow you to load modules by id.
window.require = __webpack_require__;
In the console use the following:
require(34)

You could do something similar as psimyn advised by
adding following code to some module in bundle:
require.ensure([], function () {
window.require = function (module) {
return require(module);
};
});
Use require from console:
require("./app").doSomething();
See more

After making an npm module for this (see my other answer), I did a search on npms.io and seem to have found an existing webpack-plugin available for this purpose.
Repo: https://www.npmjs.com/package/webpack-expose-require-plugin
Install
npm install --save webpack-expose-require-plugin
Usage
Add the plugin to your webpack config, then use at runtime like so:
let MyComponent = require.main("./path/to/MyComponent");
console.log("Retrieved MyComponent: " + MyComponent);
See package/repo readme page for more info.
EDIT
I tried the plugin out in my own project, but couldn't get it to work; I kept getting the error: Cannot read property 'resource' of undefined. I'll leave it here in case it works for other people, though. (I'm currently using the solution mentioned above instead)

After both making my own npm package for this (see here), as well as finding an existing one (see here), I also found a way to do it in one-line just using the built-in webpack functions.
It uses WebPack "contexts": https://webpack.github.io/docs/context.html
Just add the following line to a file directly in your "Source" folder:
window.Require = require.context("./", true, /\.js$/);
Now you can use it (eg. in the console) like so:
let MyComponent = Require("./Path/To/MyComponent");
console.log("Retrieved MyComponent: " + MyComponent);
However, one important drawback of this approach, as compared to the two solutions mentioned above, is that it seems to not work for files in the node_modules folder. When the path is adjusted to "../", webpack fails to compile -- at least in my project. (perhaps because the node_modules folder is just so massive)

Test context missing in before and after test hook in nightwatch js globals

I have multiple nightwatch tests with setup and teardown in every single test. I am trying to unify it into globalModule.js in before after(path set in globals_path in nightwatch.json).
//globalModule.js
before:function(test, callback){
// do something with test object
}
//sampletest.js
before: function(test){
..
},
'testing':function(test){
....
}
My problem is test context is not available in globalsModule.js. How do i get it there? Can someone let me know?

Test contex not available now. As said beatfactor, it will available soon.
While it not available try use local before first file, but it hack.
Also you can export all your file into one object and export it into nightwatch, but then you can use local before just in time.
For example:
var tests = {};
var befores = [];
var fs =require('fs');
var requireDir = require('require-dir');
var dirs = fs.readdirSync('build');
//if you have dirs that should exclude
var usefull = dirs.filter(function(item){
return !(item=='data')
});
usefull.forEach(function(item){
var dirObj = requireDir('../build/' + item);
for(key in dirObj){
if(dirObj.hasOwnProperty(key))
for(testMethod in dirObj[key])
if(dirObj[key].hasOwnProperty(testMethod))
if(testMethod == 'before')
befores.push(dirObj[key][testMethod]);
else
tests[testMethod] = dirObj[key][testMethod];
}
});
tests.before = function(browser){
//some global before actions here
//...
befores.forEach(function(item){
item.call(tests,browser);
});
};
module.exports = tests;
For more information https://github.com/beatfactor/nightwatch/issues/388

Develop Reference

JavaScript is the programming language of the Web.

Node.js, require all modules in folder and use loaded module directly - javascript

Related

Is it possible to launch js files with different permissions using nodejs/npm?

Exporting two module under same directory not working when requiring from same file

How to create a Node.js module from Asynchronous Function response?

How do I require() from the console using webpack?

Test context missing in before and after test hook in nightwatch js globals

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