If I have a node.js application that has hundreds of files that reference a module (say underscore) and I want to replace that module with another (say lodash) then the obvious way to do this substitution would be a global name replace and switch out the modules in the package.json file.
Is there anyway to just change the module that a name refers to so that when node.js sees require('moduleA') it actually loads 'moduleB' instead? Now I know that this would cause naming hell because anyone working on the project would see require('moduleA') and wouldn't know that the real module being loaded was 'moduleB' so ultimately you'd probably want to go with the first solution. The use case that I'm thinking of is if you want to try a few alternatives for API compatible modules to measure your application's performance (for example) with each module.
If this is an on-going thing and you want to maintain the ability to programmatically switch between the options often, such as in tests:
Instead of using require("underscore"); throughout your codebase, require a local file instead like require("./lib/underscore");, and have that file conditionally re-export underscore or a different library:
if (global.USE_LODASH) {
module.exports = require("lodash");
} else {
module.exports = require("underscore");
}
If this is a one-off thing to try out an alternative library before making the decision to switch, and you want to do this test quickly first without find-and-replacing in all of your files:
Go inside your node_modules folder, delete or rename the underscore folder, and make a symlink named underscore to the replacement module's folder. I don't recommend this as a long-term solution: running npm install again will likely undo this hack, and most projects choose to avoid checking the node_modules folder into their source repository.