I'm making a rollup-compatible plugin in Vite. (so basically a rollup-plugin).
I am using the transform hook in the plugin. The plugin takes a module name(as specified in package.json, for example "d3") as a parameter, and I want to use this parameter to apply the plugin only on the specific module.
The transform function has parameters id and code. I assumed id was the module name but it seems to be the path of the file that gets resolved when running the module.
transform(code: string, id: string) {
if(id === module_name) {
// do stuff
}
return null;
}
So, is there a way to find out the module name in the transform hook so that I can apply the plugin only on the module specified in Vite's config?
Related
How can I instantiate a class (with, say, a known empty constructor), for example:
at api/EmptyClass1.ts, I have:
export default class EmptyClass1 {
}
and, at api/EmptyClass2.ts, I have:
export default class EmptyClass2 {
}
I want this function:
function(filepath:string):any{
return Object.fromFile(filepath); //this line is mock code
}
to return a new instance of either EmptyClass1 or EmptyClass2, if the parameter filepath:string is "api/EmptyClass1.ts" or "api/EmptyClass2.ts", respectively.
The files defining the classes may not be known at the time the function is written may include any number of files. Consequently, using the import statement for each class, then using a switch, or if-then statements is not an acceptable solution.
The .ts files defining the classes are transcoded to javascript and reside in the application .build folder as .js files.
I am using typescript on node.js (recent versions).
Use require instead, and your problem will be solved. If the file may not exist, you can use optional-require if you want to have a fallback without using try/catch.
function fromFile(filepath:string):any{
// return Object.fromFile(filepath); //this line is mock code
return require(filepath);
}
Or just call require directly instead of wrapping it in another function.
Also check:
nodejs require inside TypeScript file
I can't find TypeScript definition #type/{name} for one of my installed NodeJS packages, so I attempt to write a d.ts file for it, and put the file in {project root}\typings folder. This is how I do:
// My source code: index.ts
import Helper from 'node-helper-lib';
// My definition: \typings\node-helper-lib.d.ts
declare....(something else)
declare module 'node-helper-lib' {
class Helper { ... }
export = Helper;
}
However, Visual Studio Code keeps yielding this error and puts red line under declare module 'node-helper-lib':
[ts] Invalid module name in augmentation. Module 'node-helper-lib'
resolves to an untyped module at '{project
path}\node_modules\node-helper-lib\index.js', which cannot be
augmented.
Isn't it legit that because the library is untyped, so I should be allowed to add typing to it?
UPDATE:
I am using:
TypeScript: 2.1.4
Visual Studio Code: 1.9.1
Node JS: 6.9.4
Windows 10 x64
The actual solution is given in a comment by #Paleo in #hirikarate's answer:
Imports should be declared inside the module declaration.
Example:
declare module 'node-helper-lib' {
import * as SomeThirdParty from 'node-helper-lib';
interface Helper {
new(opt: SomeThirdParty.Options): SomeThirdParty.Type
}
export = Helper;
}
After some tries and errors, I found that augmentation means "declaring a module in the same file with other module declaration(s)".
Therefore if we want to write a definition file for an untyped 3rd-party JavaScript library, we must have ONLY ONE declare module 'lib-name' in that file, and 'lib-name' must exactly match the library name (can be found in its package.json, "name" property).
On the other hand, if a 3rd-party library already has definition file .d.ts included, and we want to extend its functionalities, then we can put the additional definition in another file that we create. This is called augmenting.
For example:
// These module declarations are in same file, given that each of them already has their own definition file.
declare module 'events' {
// Extended functionality
}
declare module 'querystring' {
// Extended functionality
}
declare module '...' { ... }
I leave my discovery here just in case somebody has same question. And please correct me if I missed something.
The issue for me was that I was trying to declare the module in a .ts file. I changed it to .d.ts and it all worked just fine.
I was getting that error message too. The issue for me was that I was trying to declare another module in an existing type definition file that had a module declaration in it. After I moved the new module declaration to a new file, the error went away.
I am trying to test my Meteor application with jasmine-node. I've stubbed out some methods of Meteor framework in the helper (spec_helper.js):
var Meteor = {
startup: function (newStartupFunction) {
Meteor.startup = newStartupFunction;
},
Collection: function (collectionName) {
Meteor.instantiationCounts[collectionName] = Meteor.instantiationCounts[collectionName] ?
Meteor.instantiationCounts[collectionName] + 1 : 1;
},
instantiationCounts: {}
};
At this point I need to run the code in spec_helper.js (something equivalent of including a module in other languages). I've tried the following, but no success:
require(['spec_helper'], function (helper) {
console.log(helper); // undefined
describe('Testing', function () {
it('should test Meteor', function () {
// that's what I want to call from my stubs...
// ...it's obviously undefined
Meteor.startup();
});
});
});
Any help would be greatly appreciated.
jasmine_node will autoload helpers (any file containing the word helpers) from within your spec directory.
NOTE: you can cheat and use helper instead since it's a substring of helpers...makes more sense if you split helpers out across multiple files...singular vs plural.
If you're executing your specs from specs/unit, then create a file named specs/unit/meteor-helper.js, and jasmine_node will automagically source it for you. It will load files with the extension .js if your specs are written in vanilla JavaScript. If you pass the --coffee switch on the command line or via your grunt task config (you may even be using gulp if you're ambitious), then it will load helpers with the extensions js|coffee|litcoffee.
You should export a hash from each helper file as follows:
specs/unit/meteor-helper.js
// file name must contain the word helper
// x-helper is the convention I roll with
module.exports = {
key: 'value',
Meteor: {}
}
Then, jasmine_node will write each key to the global namespace.
This will allow you to simply type key or Meteor from your specs, or any system under test (typically code inside your lib folder that the specs are executing assertions against).
Additionally, jasmine_node will also allow you to suppress the loading of helpers via the --nohelpers switch (see code or README for more details).
This is the proper way to handle helpers for jasmine via node. You may come across some answers/examples that reference a jasmine.yml file; or maybe even spec_helper.js. But keep in mind that this is for ruby land and not node.
UPDATE: It appears jasmine-node will only source your file if it contains the word helpers. Naming each helper file x-helper.js|coffee|litcofee should do the trick. i.e. meteor-helper.coffee.
I have a requirejs module which is used as a wrapper to an API that comes from a different JS file:
apiWrapper.js
define([], function () {
return {
funcA: apiFuncA,
funcB: apiFuncB
};
});
It works fine but now I have some new use cases where I need to replace the implementation, e.g. instead of apiFuncA invoke my own function. But I don't want to touch other places in my code, where I call the functions, like apiWrapper.funcA(param).
I can do something like the following:
define([], function () {
return {
funcA: function(){
if(regularUseCase){
return apiFuncA(arguments);
} else {
return (function myFuncAImplementation(params){
//my code, instead of the external API
})(arguments);
}
},
funcB: apiFuncB
};
});
But I feel like it doesn't look nice. What's a more elegant alternative? Is there a way to replace the module (apiWrapper) dynamically? Currently it's defined in my require.config paths definition. Can this path definition be changed at runtime so that I'll use a different file as a wrapper?
Well, first of all, if you use Require.js, you probably want to build it before production. As so, it is important you don't update paths dynamically at runtime or depends on runtime variables to defines path as this will prevent you from running r.js successfully.
There's a lot of tools (requirejs plugins) out there that can help you dynamically change the path to a module or conditionnaly load a dependency.
First, you could use require.replace that allow you to change parts (or all) of a module URL depending on a check you made without breaking the build.
If you're looking for polyfilling, there's requirejs feature
And there's a lot more listed here: https://github.com/jrburke/requirejs/wiki/Plugins
I have being playing around with requirejs for the last few days. I am trying to understand the differences between define and require.
Define seems to allow for module separation and allow for dependency ordering to be adhere. But it downloads all the files it needs to begin with. Whilst require only loads what you need when you need it.
Can these two be used together and for what purposes should each of them be used?
With define you register a module in require.js that you can then depend on in other module definitions or require statements.
With require you "just" load/use a module or javascript file that can be loaded by require.js.
For examples have a look at the documentation
My rule of thumb:
Define: If you want to declare a module other parts of your application will depend on.
Require: If you just want to load and use stuff.
From the require.js source code (line 1902):
/**
* The function that handles definitions of modules. Differs from
* require() in that a string for the module should be the first argument,
* and the function to execute after dependencies are loaded should
* return a value to define the module corresponding to the first argument's
* name.
*/
The define() function accepts two optional parameters (a string that represent a module ID and an array of required modules) and one required parameter (a factory method).
The return of the factory method MUST return the implementation for your module (in the same way that the Module Pattern does).
The require() function doesn't have to return the implementation of a new module.
Using define() you are asking something like "run the function that I am passing as a parameter and assign whatever returns to the ID that I am passing but, before, check that these dependencies are loaded".
Using require() you are saying something like "the function that I pass has the following dependencies, check that these dependencies are loaded before running it".
The require() function is where you use your defined modules, in order to be sure that the modules are defined, but you are not defining new modules there.
General rules:
You use define when you want to define a module that will be reused
You use require to simply load a dependency
//sample1.js file : module definition
define(function() {
var sample1 = {};
//do your stuff
return sample1;
});
//sample2.js file : module definition and also has a dependency on jQuery and sample1.js
define(['jquery', 'sample1'], function($,sample1) {
var sample2 = {
getSample1:sample1.getSomeData();
};
var selectSomeElement = $('#someElementId');
//do your stuff....
return sample2;
});
//calling in any file (mainly in entry file)
require(['sample2'], function(sample2) {
// sample1 will be loaded also
});
Hope this helps you.
"define" method for facilitating module definition
and
"require" method for handling dependency loading
define is used to define named or unnamed modules based on the proposal using the following signature:
define(
module_id /*optional*/,
[dependencies] /*optional*/,
definition function /*function for instantiating the module or object*/
);
require on the other hand is typically used to load code in a top-level JavaScript file or within a module should you wish to dynamically fetch dependencies
Refer to https://addyosmani.com/writing-modular-js/ for more information.
require() and define() both used to load dependencies.There is a major difference between these two method.
Its very Simple Guys
Require() : Method is used to run immediate functionalities.
define() : Method is used to define modules for use in multiple locations(reuse).