Flow: requiring doesn't work with backticks

[barbalex]

// @flow

const Hapi = require(`hapi`)

gives this:

server.js:9
  9: const Hapi = require(`hapi`)
                  ^^^^^^^^^^^^^^^ The parameter passed to require() must be a literal string.

[jesseschalken]

backticks*

[barbalex]

thanks :-)

[jeffmo]

Sorry I didn't see this before, but if you wish to suppress this particular kind of error you can use the following config flag:

module.ignore_non_literal_requires=true

Note that if you do this, Flow won't be able to extract a type for the require(), though (which is why it errors by default).

[mroch]

I think we should just support template literals as long as there are no expressions

[vkurchatkin]

@jeffmo it would be nice to parse contents of template and figure out that it's static though

[mroch]

I did something similar in https://github.com/facebook/flow/commit/127f0dd28af0e73de92ec4d6336904a1411f4ec7

[EvHaus]

The changelog says this was fixed in v0.38.0 but I'm using v0.41.0 and still seeing this error:

65:         const originalCode = routeParams.component ? require(`raw-loader!./../examples/${routeParams.component}`) : null;
                                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The parameter passed to require() must be a literal string.

Any idea what could be going wrong?

[nmn]

@EvNaverniouk You are using ${routeParams.component} to inject a non-constant string into your module name. This is not allowed.

This is because flow runs staticly. It can't verify which module it will resolve to dynamically.

[EvHaus]

How could I mitigate this? Is there a way to tell Flow not to check this line? Or to accept a non-constant string for all require statements?

[futpib]

@EvNaverniouk Is this not precisely what module.ignore_non_literal_requires=true does? (mentioned above)