The specs are unclear about what kind of xref table format must be used.
In checking the validity of some pdfs in the preflight tool from Acrobat
we can guess that having the same format is the correct way to do.
The pdf in the mentioned bug, after having been changed, wasn't correctly
displayed in neither Chrome nor Acrobat: it's now fixed.
Note how we're using custom `__non_webpack_import__`-calls in the code-base, that we replace during the post-processing stage of the build, to be able to write `import`-calls that Webpack will leave alone during parsing.
This work-around is necessary since we let Babel discards all comments, given that we generally don't need/want them in the builds, hence why we cannot utilize `/* webpackIgnore: true */`-comments in the source-code.
After the changes in PR 17563 it thus seems to me that we should be able to just move this re-writing into the Babel plugin instead.
The `handler` method contained this code in an inline function, which
made the `handler` method big and harder to read. Moreover, this code
relied on variables from the outer scope, which made it harder to reason
about because the inputs and outputs weren't easily visible.
This commit fixes the problems by extracting the directory listing code
into a dedicated private method, and modernizing it to use e.g. `const`/
`let` instead of `var` and using template strings.
The `handler` method contained this code in an inline function, which
made the `handler` method big and harder to read. Moreover, this code
relied on variables from the outer scope, which made it harder to reason
about because the inputs and outputs weren't easily visible.
This commit fixes the problems by extracting the range file serving code
into a dedicated private method, and modernizing it to use e.g. `const`/
`let` instead of `var` and using template strings.
The `handler` method contained this code in an inline function, which
made the `handler` method big and harder to read. Moreover, this code
relied on variables from the outer scope, which made it harder to reason
about because the inputs and outputs weren't easily visible.
This commit fixes the problems by extracting the file serving code into
a dedicated private method, and modernizing it to use e.g. `const`/`let`
instead of `var` and using template strings.
Currently the `web/app.js` file pulls in various build-specific dependencies, via the use of import maps, and those files in turn import from `web/app.js` thus creating undesirable import cycles.
To avoid this we instead pass in a `PDFViewerApplication`-reference, immediately after it's been created, to the relevant code.
Note that we use an ESLint plugin rule, see `import/no-cycle`, that is normally able to catch import cycles. However, in this case import maps are involved which is why this wasn't caught.
Looking at the *built* files you'll notice some lines containing nothing more than a semicolon. This is the result of (mostly top-level) `if`-statements, which include `PDFJSDev`-checks, that evalute to `false` during Babel parsing.
This has always annoyed me a bit, and looking at Babel plugin it seems that we can fix this simply by *removing* the relevant nodes.
This part of the (modern) preprocessor is now dead code, since we no longer use `require` statements anywhere in the main code-base.
Note that as part of the changes leading up to PDF.js version `4` we removed all[1] the remaining `require` statements, and we also have an ESLint rule to ensure that no new ones are accidentally added.
---
[1] With two small exceptions, in benchmarking-code and in the Webpack-example.
