Require.js Can't Load Library That Defines its Own Alias - requirejs

I'm trying to bring the Underscore.String library in to a Require.js project. The library is setup to support AMD, with the following code:
} else if (typeof define === 'function' && define.amd) {
// Register as a named module with AMD.
define('underscore.string', [], function() {
return _s;
});
But I have a problem: I don't keep the library in my root path, I keep it in "ext/underscore.string". This seems to make it impossible to require the library.
I have tried requiring both "ext/underscore.string" and "underscore.string", with and without defining a path (of "underscore.string": "ext/underscore.string"). When I don't have a path, and I require "underscore.string" the file (unsurprisingly) doesn't load, and in all other cases the file loads but the library doesn't get defined.
If I try to reference the library afterwards I get:
Error: Module name "underscore.string" has not been loaded yet for
context:
... even if I do so immediately after the define line (in the code above)! In other words, if I change the code to
define('underscore.string', [], function() {
return _s;
});
console.log(require('underscore.string'))
Require tells me that "underscore.string" hasn't been loaded yet!
Can anyone help me figure out how I can bring this library in to my codebase?

In your require configuration do:
var require = {
...
map: {
"*": {
"underscore.string": "path/to/file/disregarding/baseUrl"
}
}
};
NOTE: The path to file should include the baseUrl, so in your case and assuming baseUrl="scripts", it would be something like:
"scripts/ext/underscore.string.js"
NOTE 2: It needs the .js extension, i.e. it is exact file name.

Related

Rollup - incorrect path resolution

I want to use the library ebnf from NPM and create a bundle using rollup. Since the ebnf is installed to node_modules I also use the rollup plugin rollup-plugin-node-resolve.
The problem is that ebnf contains the code require('..') which - in my case - is resolved to dist in my case. Thus it seems .. is interpreted relative to the output file instead of being relative to the source file.
This is my rollup.config.js (taken from my test repo jneuendorf/rollup-broken-resolve):
import resolve from 'rollup-plugin-node-resolve'
import commonjs from 'rollup-plugin-commonjs'
export default {
input: 'src/index.js',
output: {
file: 'dist/bundle.js',
format: 'cjs'
},
// name: 'MyModule',
plugins: [
resolve(),
commonjs(),
]
}
Is this a problem in rollup-plugin-node-resolve or am I doing something wrong?
Since some of the external libraries needed will still be available only as Common.js modules, you could also convert them to ES-Modules:
"Since most packages in your node_modules folder are probably legacy CommonJS rather than JavaScript modules, you may need to use rollup-plugin-commonjs"
https://github.com/rollup/rollup-plugin-commonjs
"Convert CommonJS modules to ES6, so they can be included in a Rollup bundle"
Just in case someone searching this issue on how to make #rollup/plugin-node-resolve (previously was rollup-plugin-node-resolve) to work with relative path. I just found the solution:
function resolve(file, origin) {
// Your way to resolve local include path
}
function pathResolve(options) {
return {
resolveId: function(file, origin) {
// Your local include path must either starts with `./` or `../`
if (file.startsWith('./') || file.startsWith('../')) {
// Return an absolute include path
return resolve(file, origin);
}
return null; // Continue to the next plugins!
}
};
}
Here is how to combine it with #rollup/plugin-node-resolve:
import {nodeResolve} from '#rollup/plugin-node-resolve';
function pathResolve(options) { /* ... */ }
export default {
// ...
plugins: [pathResolve(), nodeResolve()]
};

requirejs callback undefined

Project Structure
root
wwwroot <-- files under this location are static files public to the site
css
lib
bootstrap/js/bootstrap.js
jquery/js/jquery.js
knockout/knockout.js
requires/require.js
scripts
modules ┌───────────────┐
global.js <--│ Built modules │
dropdown.js └───────────────┘
modules
global.js ┌────────────────┐
dropdown <--│ Source modules │
dropdown.js └────────────────┘
gruntfile.js
global.cs Contents (pre-built version at ~/modules/global.js)
require.config({
baseUrl: "scripts/modules",
paths: {
jquery: "../../lib/jquery/js/jquery",
bootstrap: "../../lib/bootstrap/js/bootstrap",
knockout: "../../lib/knockout/knockout"
},
shims: {
bootstrap: {
deps: ['jquery']
}
},
});
define(function (require) {
var $ = require('jquery');
var ko = require('knockout');
var bootstrap = require('bootstrap');
});
dropdown.js Contents (pre-built version at ~/modules/dropdown.js)
define(function () {
console.log('dropdown initialized');
return 'foo';
});
HTML Page
Contains this script tag in the <head> of the page for loading requires config:
<script src="~/lib/requirejs/require.js" data-main="scripts/modules/global"></script>
In the body of the HTML page, I have the following:
<script>
require(['global'], function () {
require(['dropdown'], function (dropdown) {
console.log(dropdown);
});
});
</script>
Issue
The dropdown callback is undefined instead of the expected "foo" string that I'm returning from the defined module.
In fact, the console does not contain a log item for "dropdown initialized" either. This makes me believe the module is not being invoked somehow? However, it's strange the dropdown.js is present in F12 debugger as a script loaded into the page. Therefore, requires did make a call to load it, but did not run the contents of the define?
Noteworthy mentions
I'm using r.js to optimize and build. Both global.js and dropdown.js are processed over.
The name assigned to the dropdown module by r.js processing is "modules/dropdown/dropdown.js". I'm unsure if I should be using this somehow, or if I'm referring to the module correctly as just dropdown and relying on my baseUrl config having the correct path.
Edit #1
I have added the r.js build configuration used with grunt per commenter request. In conjunction, I updated the file structure to include the overall project structure, instead of just the runtime public wwwroot structure.
The r.js process will compile built forms of global.js + other modules in ~/wwwroot/scripts/modules from the source location ~/modules in summary.
function getRequireJsConfiguration() {
var baseUrl = './';
var paths = {
jquery: "wwwroot/lib/jquery/js/jquery",
bootstrap: "wwwroot/lib/bootstrap/js/bootstrap",
knockout: "wwwroot/lib/knockout/knockout"
};
var shims = {
bootstrap: {
deps: ['jquery']
}
};
var optimize = 'none';
var configuration = {};
var jsFilePaths = grunt.file.expand('modules/**/*.js');
jsFilePaths.forEach(function (jsFilePath) {
var fileName = jsFilePath.split('/').pop();
if (configuration[fileName]) {
throw 'Duplicate module name conflict: ' + fileName;
}
configuration[fileName] = {
options: {
baseUrl: './',
name: jsFilePath,
out: 'wwwroot/scripts/modules/' + fileName,
paths: paths,
shims: shims,
optimize: optimize,
exclude: ['jquery', 'knockout', 'bootstrap']
}
};
});
configuration['global'] = {
options: {
baseUrl: './',
name: 'modules/global.js',
out: 'wwwroot/scripts/modules/global.js',
paths: paths,
shims: shims,
optimize: optimize,
}
};
return configuration;
}
Edit #2
Thought it'd be a good idea to include the versions of requirejs packages I'm using:
requirejs: 2.1.15
grunt-contrib-requirejs: 0.4.4
Thanks.
The name assigned to the dropdown module by r.js processing is "modules/dropdown/dropdown.js". I'm unsure if I should be using this somehow, or if I'm referring to the module correctly as just dropdown and relying on my baseUrl config having the correct path.
In a sense, yes, you should be using that full path. That's what Require refers to as the module id - "modules/dropdown/dropdown" (if the .js in the above output was real, I suggest stripping that extension in the "name" config. .js is assumed by RequireJS, you don't want that string in your module ids). The basePath is used, when given IDs, to transform some unknown ID to a file path (e.g. 'bootstrap' id -> (applying path config) -> '../../lib/bootstrap/js/bootstrap' -> (applying base URL) -> 'scripts/modules/../../lib/bootstrap/js/bootstrap').
Really, though, just allowing r.js to concatenate everything into one file
is the preferred way to go. You could use the include option to include modules un-referenced by global.js in with the optimized bundle, too ( https://github.com/jrburke/r.js/blob/master/build/example.build.js#L438 )
As to your specific problem: your lazy require(['dropdown']) call is misleading you. By combining the requested module id with the basePath, RequireJS comes up with the URL you want - scripts/modules/dropdown - which defines a module with the module id scripts/module/dropdown - but since you requested the module id dropdown, you get nothing. (I would've guessed you'd get a RuntimeError instead of undefined, but I suppose that's how things go). One way or another you need to address the id/path mismatches.
Although I have resolved my issue with the hints wyantb's answer provided, I've since changed my approach to a single file concat due to the simplicity it brings. I still wanted to post the specifics of how I solved this question's issue for anyone else to happens along it.
In the grunt build configuration options, I added the onBuildWrite field to transform the content, so my assigned module IDs lined up with how I was lazily loading them.
onBuildWrite: function (moduleName, path, contents) {
return contents.replace(/modules\/global.js/, 'global');
}
This code is specifically for the global.js file. I implemented a similar onBuildWrite for the other module files (in the foreach loop). The transformation will essentially strip the path and extension from the module name that r.js assigns.
Here are some examples of before and after:
Before After
/modules/global.js global
/modules/dropdown/dropdown.js dropdown
/modules/loginButton/loginButton.js loginButton
Therefore, when I load the modules using the HTML script from my original question, requirejs resolves and finds a match.
Either require by path or define global and dropdown in global.cs
require(['./global'], function () {
require(['./dropdown'], function (dropdown) {
console.log(dropdown);
});
});

No dependencies defined when they are loaded via absolute paths

I have some module like this:
define('hello',[],
function()
{
return {
say: function(word) { console.log("Hello, "+word) },
};
});
And I'm using it like this (without any require.config) :
require(["hello"],
function(hello)
{
console.log("main",hello);
hello.say("main");
});
So far, so good.
But when I'm trying to require the same module with an absolute path, I've got my dependence module undefined:
require(["http://example.com/js/hello.js"],
function(hello)
{
console.log("main",hello);
hello.say("main");
});
Console:
main undefined
Uncaught TypeError: Cannot read property 'say' of undefined // Oops!
Why is it so?
Named module (define("NAME", [ ... ], function() { ... })) is meant to be required under exact that name. When it is required with a URL it is loaded correctly, but registers itself under its "desired" name, after which requirejs loses track of it still looking for a module with a name http://example.com/js/hello.js.
The reason the name given to define() isn't overriden with the one under which the module was required is to allow multiple module definitions to coexist in the file, for example after optimization. Optimizer will convert all define calls to the form with explicit name.
The reason the absolute name isn't converted to a module id is that this conversion is impossible. All the configuration options of requirejs determine how to convert module id to script location, not other way around.
Documentation discourages use of the named modules:
These are normally generated by the optimization tool. You can explicitly name modules yourself, but it makes the modules less portable ... It is normally best to avoid coding in a name for the module and just let the optimization tool burn in the module names...
Anonymous module, i.e.:
define([],
function()
{
return {
say: function(word) { console.log("Hello, "+word) },
};
});
works with either module id ("hello") or absolute path, because it is first registered without a name and later receives the name under which it was required.

Packaging a Library for AMD/Require.js With Dependencies

I thought I'd be able to expose my JS library to Require.js, and make it dependent on jQuery, Backbone, and Underscore, with the following code:
} else if (typeof define === 'function' && define.amd) {
define(['backbone', 'jquery', 'underscore'], function(Backbone, $, _) {
return factory(root, Backbone, $, _);
});
where factory is a function that returns my library. That seems ok, except that the module name "backbone" appears to be hard-coded to the filesystem path "{Require root}/backbone". Even if I define a path in my Require config before requiring the library:
'backbone': '/some/other/path/backbone'
my browser still gives me an error:
GET http://localhost:8000/js/backbone.js 404 (NOT FOUND)
Can anyone explain how I can define "this library depends on Backbone" without saying "this library requires exactly {root}/backbone.js"?
That is exactly what Backbone does so I'm not sure why you're having problems. Can you post the code of how you're requiring this library and where you're defining your require config?
if (typeof define === 'function' && define.amd) {
define(['underscore', 'jquery', 'exports'], function(_, $, exports) {

How do you use a requirejs friendy JavaScript file without using requirejs? I.o.w. how to demodularize?

Suppose I have a JS-library, neatly wrapped in a define('myModule', function(myModule) { return myModule.someObject; });
How could I bind the myModule.someObject to global scope (please don't ask why, I know modular programming has a lot of benefits over putting stuff on the global scope), without using requirejs or any other module handling framework?
The thing is: while developing, I'd like to use requirejs. The library that we build should be able to be included by somebody using requirejs (AMD, CommonJS, whatever), but should also be available as window.SomeObject for the people that don't want to use require just for the sake of being able to use our SomeObject. After the development phase, all code will be minified and obfuscated to a single JS file.
I think I'm just googling with the wrong search terms, because all I can find is an answer to the question how to include code that isn't wrapped in a requirejs friendly define function.
Any ideas on this would greatly be appreciated. Thanks!
--- EDIT ---
My file (before it all started) looked like:
(function(define, global) {
define([a,b,c],function(theA, theB, theC) {
return theA + theB + theC; // or something, it doesn't matter
});
})(define, this);
I'm thinking of something like this:
(function(define, global) {
// same as above
})(typeof define === 'function'
? define
: function(factory /* need more args? */) { /* solution here */ }, this);
But I'm not sure how to implement it properly...
I guess you need to wrap your modules so that they could be accessed without requirejs:
if ( typeof define === "function" && define.amd ) {
define( "mymodule", [], function () {
// do your logic
return mystuff;
} );
} else {
// do your logic
window.mystuff = mystuff;
}
Look at jQuery as an example.
I would refrain from giving your module an id if you can help it, it makes it less portable. jQuery is incredibly annoying that it forces you to set a jquery path option, but they did it for compatibility reasons. Always prefer anonymous modules if you can.
From the jQuery source
// Register as a named AMD module, since jQuery can be concatenated with other
// files that may use define, but not via a proper concatenation script that
// understands anonymous AMD modules. A named AMD is safest and most robust
// way to register. Lowercase jquery is used because AMD module names are
// derived from file names, and jQuery is normally delivered in a lowercase
// file name. Do this after creating the global so that if an AMD module wants
// to call noConflict to hide this version of jQuery, it will work.
James Burke goes into a little more detail here also.
I would instead use a more common example from the umdjs repository:
(function (root, factory) {
if (typeof define === 'function' && define.amd) {
// AMD. Register as an anonymous module.
define(['b'], factory);
} else {
// Browser globals
root.amdWeb = factory(root.b);
}
}(this, function (b) {
//use b in some fashion.
// Just return a value to define the module export.
// This example returns an object, but the module
// can return a function as the exported value.
return {};
}));
For another example that also supports CommonJS, check out the reqwest library:
!function (name, context, definition) {
if (typeof module != 'undefined' && module.exports) module.exports = definition()
else if (typeof define == 'function' && define.amd) define(definition)
else context[name] = definition()
}('reqwest', this, function () {
return {};
});
How can I provide a library to others that does not depend on RequireJS?
This allows you to ship code that does not ship with all of RequireJS, and allows you to export any kind of API that works on a plain web page without an AMD loader.
You need to make a build config file which uses wrap and almond.
It all feels pretty dirty, but I've had it working (by following the almond ReadMe) with exactly what you're describing.

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