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Jonas Jenwald 2f3805efbc Switch to using ESLint, instead of JSHint, for linting
*Please note that most of the necessary code adjustments were made in PR 7890.*

ESLint has a number of advantageous properties, compared to JSHint. Among those are:
 - The ability to find subtle bugs, thanks to more rules (e.g. PR 7881).
 - Much more customizable in general, and many rules allow fine-tuned behaviour rather than the just the on/off rules in JSHint.
 - Many more rules that can help developers avoid bugs, and a lot of rules that can be used to enforce a consistent coding style. The latter should be particularily useful for new contributors (and reduce the amount of stylistic review comments necessary).
 - The ability to easily specify exactly what rules to use/not to use, as opposed to JSHint which has a default set. *Note:* in future JSHint version some of the rules we depend on will be removed, according to warnings in http://jshint.com/docs/options/, so we wouldn't be able to update without losing lint coverage.
 - More easily disable one, or more, rules temporarily. In JSHint this requires using a numeric code, which isn't very user friendly, whereas in ESLint the rule name is simply used instead.

By default there's no rules enabled in ESLint, but there are some default rule sets available. However, to prevent linting failures if we update ESLint in the future, it seemed easier to just explicitly specify what rules we want.
Obviously this makes the ESLint config file somewhat bigger than the old JSHint config file, but given how rarely that one has been updated over the years I don't think that matters too much.

I've tried, to the best of my ability, to ensure that we enable the same rules for ESLint that we had for JSHint. Furthermore, I've also enabled a number of rules that seemed to make sense, both to catch possible errors *and* various style guide violations.

Despite the ESLint README claiming that it's slower that JSHint, https://github.com/eslint/eslint#how-does-eslint-performance-compare-to-jshint, locally this patch actually reduces the runtime for `gulp` lint (by approximately 20-25%).

A couple of stylistic rules that would have been nice to enable, but where our code currently differs to much to make it feasible:
 - `comma-dangle`, controls trailing commas in Objects and Arrays (among others).
 - `object-curly-spacing`, controls spacing inside of Objects.
 - `spaced-comment`, used to enforce spaces after `//` and `/*. (This is made difficult by the fact that there's still some usage of the old preprocessor left.)

Rules that I indend to look into possibly enabling in follow-ups, if it seems to make sense: `no-else-return`, `no-lonely-if`, `brace-style` with the `allowSingleLine` parameter removed.

Useful links:
 - http://eslint.org/docs/user-guide/configuring
 - http://eslint.org/docs/rules/
2016-12-16 21:06:36 +01:00
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web Switch to using ESLint, instead of JSHint, for linting 2016-12-16 21:06:36 +01:00
.editorconfig Uses editorconfig to maintain consistent coding styles 2015-11-14 07:32:18 +05:30
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.eslintrc Switch to using ESLint, instead of JSHint, for linting 2016-12-16 21:06:36 +01:00
.gitattributes Fixing C++,PHP and Pascal presence in the repo 2015-10-29 13:03:51 -05:00
.gitignore Added svg export tool 2014-08-14 23:18:19 +05:30
.gitmodules Update fonttools location and version (issue 6223) 2015-07-17 12:51:09 +02:00
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make.js Switch to using ESLint, instead of JSHint, for linting 2016-12-16 21:06:36 +01:00
package.json Switch to using ESLint, instead of JSHint, for linting 2016-12-16 21:06:36 +01:00
pdfjs.config Release of 1.6.210 2016-10-04 12:19:51 -05:00
README.md Add HTTPS support 2016-11-04 15:55:56 +01:00

PDF.js

PDF.js is a Portable Document Format (PDF) viewer that is built with HTML5.

PDF.js is community-driven and supported by Mozilla Labs. Our goal is to create a general-purpose, web standards-based platform for parsing and rendering PDFs.

Contributing

PDF.js is an open source project and always looking for more contributors. To get involved checkout:

For further questions or guidance feel free to stop by #pdfjs on irc.mozilla.org.

Getting Started

Online demo

Browser Extensions

Firefox (and Seamonkey)

PDF.js is built into version 19+ of Firefox, however one extension is still available:

  • Development Version - This extension is mainly intended for developers/testers, and it is updated every time new code is merged into the PDF.js codebase. It should be quite stable, but might break from time to time.

Chrome

  • The official extension for Chrome can be installed from the Chrome Web Store. This extension is maintained by @Rob--W.
  • Build Your Own - Get the code as explained below and issue gulp chromium. Then open Chrome, go to Tools > Extension and load the (unpackaged) extension from the directory build/chromium.

Getting the Code

To get a local copy of the current code, clone it using git:

$ git clone git://github.com/mozilla/pdf.js.git
$ cd pdf.js

Next, install Node.js via the official package or via nvm. You need to install the gulp package globally (see also gulp's getting started):

$ npm install -g gulp-cli

If everything worked out, install all dependencies for PDF.js:

$ npm install

Finally you need to start a local web server as some browsers do not allow opening PDF files using a file:// URL. Run

$ gulp server

and then you can open

It is also possible to view all test PDF files on the right side by opening

Building PDF.js

In order to bundle all src/ files into two productions scripts and build the generic viewer, issue:

$ gulp generic

This will generate pdf.js and pdf.worker.js in the build/generic/build/ directory. Both scripts are needed but only pdf.js needs to be included since pdf.worker.js will be loaded by pdf.js. If you want to support more browsers than Firefox you'll also need to include compatibility.js from build/generic/web/. The PDF.js files are large and should be minified for production.

Using PDF.js in a web application

To use PDF.js in a web application you can choose to use a pre-built version of the library or to build it from source. We supply pre-built versions for usage with NPM and Bower under the pdfjs-dist name. For more information and examples please refer to the wiki page on this subject.

Learning

You can play with the PDF.js API directly from your browser through the live demos below:

The repo contains a hello world example that you can run locally:

For an introduction to the PDF.js code, check out the presentation by our contributor Julian Viereck:

You can read more about PDF.js here:

Even more learning resources can be found at:

Questions

Check out our FAQs and get answers to common questions:

Talk to us on IRC:

  • #pdfjs on irc.mozilla.org

Join our mailing list:

Subscribe either using lists.mozilla.org or Google Groups:

Follow us on twitter: @pdfjs

Weekly Public Meetings