I'm using npm and have my libraries in node-modules.
When I use import or require, for example import A from 'my_lib', somehow library gets resolved (something is imported from my_lib).
How does the library get resolved?
I think index.js file get's checked if it exists (similar to when I import from my custom folder with ./my_folder, the ./my_folder/index.js is checked)? What are the rules?
NOTE: Sometimes I use webpack, and I think in webpack there is resolve.mainFiles property with default value of ['index'] meaning if folder is specified it uses index.js.
But I'm using for example react library which doesn't have index.js in root folder and it still resolves properly.
Does the resolver look in package.json if the specified folder has one?
Related
I'm using a library vtk.js. VTK has a special design of classes (https://kitware.github.io/vtk-js/docs/develop_class.html). When I write a class I need to import macro.js module which exposes several base methods such as getters/setters/newInstance etc (https://github.com/Kitware/vtk-js/blob/master/Sources/macro.js).
Looks like CRA uses some special loader for macro.js files. I get an error when trying to import such a file (SyntaxError: Cannot use import statement outside a module). If I copy an original file macro.js from #kitware/vtk.js to my local source folder I still get an error. Even if I remove all the contents of macro.js file I get an error (The macro imported from "../macro" must be wrapped in "createMacro" which you can get from "babel-plugin-macros". Please refer to the documentation to see how to do this properly: https://github.com/kentcdodds/babel-plugin-macros/blob/master/other/docs/author.md#writing-a-macro). However, when I rename macro.js to macro2.js the error is gone.
Is there some way how can I disable this macro loader?
I am creating a VSCode extension, and following the getting started guide (https://code.visualstudio.com/api/get-started/your-first-extension) have used yeoman scaffold to get started. I created a new file, newModule.js in the same directory and want to import it as a module for use in the main extension.js script. I then do:
const newModule = require('./newModule.js');
This throws an error:
cannot find module 'newModule' require stack: -
This problem disappears if I copy my file to the node_modules folder created by default. I would like to know what is going on here, and what the best way of handling imports is when working with javascript/Node.js/vs-extensions.
I also notice that node_modules folder is not pushed to github by default, why?
The node_modules folder is for storing all the code from the libraries and packages you are using. It is excluded from git because it is a waste of space and a distraction to store them all in your versioning-control, as you can just re-download them anytime.
Just put your module in the same /src directory, and use the import syntax to import it, instead of require.
import newModule from './newModule';
For example, see how it is done in this sample code.
Please instead
const newModule = require('./newModule.js');
Try this
import newModule from './newModule');
// ^^ Do not use file extension
Also make sure that the file you are calling is in the same directory
I just want to know one thing,
Consider i have defined a dependency in package.json file like "some-library": "1.0.0"
and installed it using npm install. which will include all dependencies to node_modules folder.
then am importing a Component from that dependency using
import SomeLibrary from 'some-library;
when we do this where this import statement start looking for the component which we are importing ?
can some one explain in a better way. i have googled alot but didn't find any relevant answer. Thanks in advance.
At it's core, the import statement uses the same module resolution method as require().
So for installed modules it goes like this: By calling require(X), it gets a list of all the 'node_modules' directories present in the parent directories. Then, it tries to load the X module from each of those directories (either as a single file, or a directory.)
https://nodejs.org/api/modules.html#modules_all_together
I am trying to alter the following build task written in Typescript in the following project:
https://github.com/Microsoft/app-store-vsts-extension/blob/master/Tasks/app-store-promote/app-store-promote.ts
I need an import like the one shown below (or something else that lets me uses the methods in the ios-signing-common module):
import sign = require('ios-signing-common/ios-signing-common');
That import is used in another file in another project:
https://github.com/Microsoft/vsts-tasks/blob/master/Tasks/XamariniOS/xamarinios.ts, however that project is also the same as the ios-signing-common exists in.
https://github.com/Microsoft/vsts-tasks/blob/master/Tasks/Common/ios-signing-common/ios-signing-common.ts
So is it possible to import the ios-signing-common module into the app-store-promote file?
I have tried adding the github path "Microsoft/vsts-tasks" as dependency in package.json, and it downloads it to node_modules, but I still can't resolve the ios-signing-common module.
I hope that any of you can lead me to a solution. :)
I guess I just needed to read up on how module resolving works.
I solved it by adding vsts-tasks as dependency in package.json:
"dependencies": {
"vsts-task-lib": "^0.9.7",
"vsts-tasks": "Microsoft/vsts-tasks"
},
Then I changed the require path to the following:
import sign = require('Agent.Tasks/Tasks/Common/ios-signing-common/ios-signing-common');
And it works!
EDIT - It could compile, but doesn't seem to work when I run it. It fails in the script because it can't find Agent.Tasks/Tasks/Common/ios-signing-common/ios-signing-common.
I'm trying to use tracking-js library in my project I'm using react but I dont know if I'm doing anything wrong but keep showing that the module is not found, I already check my package.json and the module install. So this is how I require the module:
const tracking = require("tracking");
what am I doing wrong?
For node, including node-based build tools, first make sure that the module is present. Keep in mind that require does not care about the package.json of your app, only about the module files being present.
Check if node_modules/tracking is present.
Make sure the "main" JS file can be found. If there's a node_modules/tracking/package.json file, see if it has a main property and if the file it references exists. If there is no main property, make sure there's an index.js in the root of the module directory.
If all this is fine and you're getting the module not found error at runtime in client-side JavaScript, then your bundling config may be incorrect, and your webpack/browserify/whatever config will have to be scrutinized for bugs.