Node.JS export function without object wrapper - function

I am looking at Node.JS request and notice that you can use
var request = require('request');
request(...)
But when I try to do something similar like in the module I try
exports = function() {}
it does not work. The only way I know to use is
var request = require('request').request;
request(...)
and
exports.request = function() {}
How can I set the whole export to a function instead of adding a function to the export object?
A hint might be available in the request source code but I am finding it hard to figure out what is going on. Can you help?

You need to overwrite it as
module.exports = function() {}
Merely writing exports = function() {} creates a new local variables called exports and hides the exports variable living in module.exports

Related

Disable side panel when exporting Kepler.gl map?

I loaded my data into kepler.gl (https://kepler.gl/) and created a visual I would like to post online by embedding the code into a blogpost.
However, I want the readers/users not to be able to see and access the side panel, but rather only with the main view of the map.
Is there any way to do so or any parameters I can change when exporting the html?
To solve the issue, one must replace the reducers block:
const reducers = (function createReducers(redux, keplerGl) {
return redux.combineReducers({
// mount keplerGl reducer
keplerGl: keplerGl.keplerGlReducer
});
}(Redux, KeplerGl));
With the following:
const reducers = (function createReducers(redux, keplerGl) {
const customizedKeplerGlReducer = keplerGl.keplerGlReducer.initialState({
uiState: {readOnly: true}
});
return redux.combineReducers({
// mount keplerGl reducer
keplerGl: customizedKeplerGlReducer
});
}(Redux, KeplerGl));
And in the end, change the line with addDataToMap to:
store.dispatch(keplerGl.addDataToMap(loadedData, {readOnly: true}));

How to load and use environment-related values in config phase

I would like to deploy my web application to several environments. Using Continuous Integration I can run a task to generate a config.json for a particular environment. This file will contain, among others, the particular URLs to use for it.
{
"baseUrl": "http://www.myapp.es/",
"baseApiUrl": "http://api.myapp.es/",
"baseAuthUrl": "http://api.myapp.es/auth/"
}
The issue comes up when I try to set my different services through providers in the config phase. Of course, services are not available yet in the phase so I cannot use $http to load that json file and set my providers correctly.
Basically I would like to do something like:
function config($authProvider) {
$authProvider.baseUrl = config.baseAuthUrl;
}
Is there a way to load those values on runtime from a file? The only thing I can think about is having that mentioned task altering this file straight away. However I have several modules and therefore, that would have to do in all of them which doesn´t seem right.
You can create constants in the config of your main module:
Add $provide as a dependency in your config method
use the provider method to add all constants like this
$provide.provider('BASE_API_URL', {
$get: function () {
return 'https://myexample.net/api/';
}
});
You can use BASE_API_URL as a dependency in your services.
I hope this helps
Optionally you can set the url depending of your environment:
$provide.provider('BASE_API_URL', {
$get: function () {
if(window.location.hostname.toLowerCase() == 'myapp.myexample.net')
{
return 'https://myexample.net/api/' //pre-production
}else
{
return 'http://localhost:61132/'; //local
}
}
});
Regards!
Finally, the solution was generating an angular constants file using templating (gulp-template) through a gulp task. At the end, I am using a yaml file instead a json one (which is the one generated my CI engine with the proper values for the environment I want to deploy to).
Basically:
config.yml
baseUrl: 'http://www.myapp.es/'
baseApiUrl: 'http://api.myapp.es/'
auth:
url: 'auth/'
config.module.constants.template
(function () {
'use strict';
angular
.module('app.config')
.constant('env_variables', {
baseUrl: '<%=baseUrl%>',
baseApiUrl: '<%=baseApiUrl%>',
authUrl: '<%=auth.url%>'
});
}());
gulpfile.js
gulp.task('splicing', function(done) {
var yml = path.join(conf.paths.src, '../config/config.yml');
var json = yaml.safeLoad(fs.readFileSync(yml, 'utf8'));
var template = path.join(conf.paths.src, '../config/config.module.constants.template');
var targetFile = path.join(conf.paths.src, '/app/config');
return gulp.src(template)
.pipe($.template(json))
.pipe($.rename("config.module.constants.js"))
.pipe(gulp.dest(targetFile), done);
});
Then you just inject it in the config phase you need:
function config($authProvider, env_variables) {
$authProvider.baseUrl = env_variables.baseApiUrl + env_variables.authUrl;
}
One more benefit about using gulp for this need is that you can integrate the generation of these constants with your build, serve or watch tasks and literally, forget about doing any change from now on. Hope it helps!

react-router + history.pushState not working

Can I get some help the proper setup of history library with react-router, the docs somewhere says that I have to use a mixin to use history from reactrouter but somewhere else tells me that I have to import history library to acomplish the task. It's so confusing
You only need to import the history library if you are going to be changing the default settings for react-router and that's only for when you setup your router. Otherwise, you don't need to.
Regardless, to use history.pushState, you do need to use the mixin. If using React Router 1.0.0-rc3, you would do as follows (a simple example but should get the point across):
var React = require('react');
var History = require('react-router').History;
var Link = React.createClass({
mixins: [ History ],
_handleClick: function(){
this.history.pushState(null, "/example-route");
},
render: function() {
return (
<div onClick={this._handleClick}>
Link
</div>
);
},
});
module.exports = Link;

Gulp: how to pass parameters from watch to tasks

With gulp you often see patterns like this:
gulp.watch('src/*.jade',['templates']);
gulp.task('templates', function() {
return gulp.src('src/*.jade')
.pipe(jade({
pretty: true
}))
.pipe(gulp.dest('dist/'))
.pipe( livereload( server ));
});
Does this actually pass the watch'ed files into the templates task? How do these overwrite/extend/filter the src'ed tasks?
I had the same question some time ago and came to the following conclusion after digging for a bit.
gulp.watch is an eventEmitter that emits a change event, and so you can do this:
var watcher = gulp.watch('src/*.jade',['templates']);
watcher.on('change', function(f) {
console.log('Change Event:', f);
});
and you'll see this:
Change Event: { type: 'changed',
path: '/Users/developer/Sites/stackoverflow/src/touch.jade' }
This information could presumably be passed to the template task either via its task function, or the behavior of gulp.src.
The task function itself can only receive a callback (https://github.com/gulpjs/gulp/blob/master/docs/API.md#fn) and cannot receive any information about vinyl files (https://github.com/wearefractal/vinyl-fs) that are used by gulp.
The source starting a task (.watch in this case, or gulp command line) has no effect on the behavior of gulp.src('src-glob', [options]). 'src-glob' is a string (or array of strings) and options (https://github.com/isaacs/node-glob#options) has nothing about any file changes.
Hence, I don't see any way in which .watch could directly affect the behavior of a task it triggers.
If you want to process only the changed files, you can use gulp-changed (https://www.npmjs.com/package/gulp-changed) if you want to use gulp.watch, or you cold use gulp-watch.
Alternatively, you could do this as well:
var gulp = require('gulp');
var jade = require('gulp-jade');
var livereload = require('gulp-livereload');
gulp.watch('src/*.jade', function(event){
template(event.path);
});
gulp.task('templates', function() {
template('src/*.jade');
});
function template(files) {
return gulp.src(files)
.pipe(jade({
pretty: true
}))
.pipe(gulp.dest('dist/'))
}
One of the possible way to pass a parameter or a data from your watcher to a task. Is through using a global variable, or a variable that is in both blocks scops. Here is an example:
gulp.task('watch', function () {
//....
//json comments
watch('./app/tempGulp/json/**/*.json', function (evt) {
jsonCommentWatchEvt = evt; // we set the global variable first
gulp.start('jsonComment'); // then we start the task
})
})
//global variable
var jsonCommentWatchEvt = null
//json comments task
gulp.task('jsonComment', function () {
jsonComment_Task(jsonCommentWatchEvt)
})
And here the function doing the task work in case it interest any one, But know i didn't need to put the work in such another function i could just implemented it directly in the task. And for the file you have your global variable. Here it's jsonCommentWatchEvt. But know if you don't use a function as i did, a good practice is to assign the value of the global variable to a local one, that you will be using. And you do that at the all top entry of the task. So you will not be using the global variable itself. And that to avoid the problem that it can change by another watch handling triggering. When it stay in use by the current running task.
function jsonComment_Task(evt) {
console.log('handling : ' + evt.path);
gulp.src(evt.path, {
base: './app/tempGulp/json/'
}).
pipe(stripJsonComments({whitespace: false})).on('error', console.log).
on('data', function (file) { // here we want to manipulate the resulting stream
var str = file.contents.toString()
var stream = source(path.basename(file.path))
stream.end(str.replace(/\n\s*\n/g, '\n\n'))
stream.
pipe(gulp.dest('./app/json/')).on('error', console.log)
})
}
I had a directory of different json's files, where i will use comments on them. I'm watching them. When a file is modified the watch handling is triggered, and i need then to process only the file that was modified. To remove the comments, i used json-comment-strip plugin for that. Plus that i needed to do a more treatment. to remove the multiple successive line break. Whatever, at all first i needed to pass the path to the file that we can recover from the event parameter. I passed that to the task through a global variable, that does only that. Allow passing the data.
Note: Even though that doesn't have a relation with the question, in my example here, i needed to treat the stream getting out from the plugin processing. i used the on("data" event. it's asynchronous. so the task will mark the end before the work completely end (the task reach the end, but the launched asynchronous function will stay processing a little more). So the time you will get in the console at task end, isn't the time for the whole processing, but task block end. Just that you know. For me it doesn't matter.

How to pass a parameter to gulp-watch invoked task

I am trying to pass a parameter to a task that is being invoked by gulp-watch. I need it because I am trying to build a modular framework.
So if a file changes in module 1, the other modules don't need to be rebuild.
And I want just one function to create the concatted & uglified files per module.
This is what I got so far:
//here I need the 'module' parameter
gulp.task('script', function(module) { ... }
gulp.task('watch', function() {
gulp.watch('files/in/module1/*.js', ['script']); //here I want to pass module1
gulp.watch('files/in/module2/*.js', ['script']); //here I want to pass module2
});
A lot of the documentation/examples seems to be outdated (gulp.run(), gulp.start()).
I hope someone can help me out here.
I had the very same issue, searched for a while, and the "cleanest" way I came up with, uses the .on() event handler of gulp.watch(), and the .env property of gulp-util:
var gulp = require('gulp');
$.util = require('gulp-util');
var modules = {
module1: {}, // awesome module1
module2: {} // awesome module2
};
gulp.task('script', function(){
var moduleName = $.util.env.module;
// Exit if the value is missing...
var module = modules[moduleName];
if (!module) {
$.util.log($.util.colors.red('Error'), "Wrong module value!");
return;
}
$.util.log("Executing task on module '" + moduleName + "'");
// Do your task on "module" here.
});
gulp.task('watch', function () {
gulp.watch(['files/in/module1/*.js'], ['script']).on('change', function () {
$.util.env.module = 'module1';
});
gulp.watch(['files/in/module2/*.js'], ['script']).on('change', function () {
$.util.env.module = 'module2';
});
});
gulp-util also comes in handy if you need to pass (global) parameters from the shell:
[emiliano#dev ~]# gulp script --module=module1 --minify
Hope this helps someone else out there!
Regards.
In that i will answer directly the question "How to pass a parameter to gulp-watch invoked task"
My way of doing, and one of the possibility i see, is to use a global variable to pass the value between the two blocks. you set it just before launching the task in the watcher. And in the task, just at the start you pass it to a local variable.
See this answer for more details: https://stackoverflow.com/a/49733123/7668448
In what you want to achieve, you can too use just one watcher over the directory that hold all modules. If so is the structure. Then when a change happen, you can recover the changed file path. From that you can deduce what module does belong to. By getting the Module folder. That way you will not need to add a new watcher for each new module. Which can be nice when there is multiple contributors to the project for example when working on open source. And you do it one time, and don't have to care about adding anything. Just like with the delegation principle, with DOM event handling when there is multiple elements. Even if the chosen structure, doesn't have all the modules in one directory. You can stay pass multiple globs to the one watcher.
gulp.watch(['glob1/**/*.js', 'glob2/**/*.js',...], function(evt) {/*.....*/});
And following the structure you have, you can work your way to deduce what module is.
For the watcher here how i suggest you do it:
watch('./your/allModulesFolder/**/*.js', function (evt) {
rebuildModulWatchEvt = evt; //here you update the global var
gulp.start('rebuildModul'); // you start the task
})
The evt here hold multiple info: cwd, base, state, _contents ...etc And what interest us is path. So evt.path will give you the path of the changed file.
In your task either you do that:
gulp.task('rebuildModul', function() {
let evt = rebuildModulWatchEvt; // at all start you pass it to a local var
let filePath = evt.path; // how you get the changed file path
// your code go here for the rest, following your structure, get the path for the module folder
});
or you use a function :
gulp.task('rebuildModul', function() {
rebuildModulTaskRun(rebuildModulWatchEvt);
});
function rebuilModulTaskRun(evt) {
let filePath = evt.path;
// your code go here for the rest, following your structure, get the path for the module folder
}