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New Member

PCF - possible webpack issue with Express npm module


When using the Express npm module within a PCF control I'm getting the following warning and then a lot of errors:

WARNING in ./node_modules/express/lib/view.js 74:13-25
Critical dependency: the request of a dependency is an expression
@ ./node_modules/express/lib/application.js
@ ./node_modules/express/lib/express.js
@ ./node_modules/express/index.js


The advice I've found online is to use webpack-node-externals to exclude Express from being bundled.  If I look at webpackConfig.js in my PCF control then node modules are already excluded.  If I use webpack-node-externals anyway then this resolves the build errors but then my control doesn't load.


I'd be really grateful for any advice.





New Member

Adding the following code to the webpack config seems to have fixed it:

externals: [{ 'express': { commonjs: 'express' } }]

Unfortunately, that's only going to solve your problem temporarily. An Initialized PCF attaches to npm install and writes over the webpack config a bit indelicately. So, the next time you (or someone who grabs your code) run npm install, it will overwrite your change and you'll need to edit config again.


(not the answer you were hoping for, I am sure)


@HemantG is this a known issue?

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