Issue 4993 - Add operator-linebreak rule to our JavaScript style guide

pages/coding-style.html

 title=Coding Style
 
 
 <h2 id="precedence">{{s1 Precedence}}</h2>
 
 <p>{{s2 The Adblock Plus coding style is based on others. Our rules (both general and language specific) always overrule referenced style guides. The language specific sections overrule the general section.}}</p>
 
 <h2 id="consistency">{{s3 Consistency}}</h2>
 
 <p>{{s4 Consistency is most important: Be consistent within functions, files, modules and projects. Making existing code conform with this style guide is fine, but it should happen in dedicated commits, preferably for a whole module or project at once.}}</p>
 
 <h2 id="general">{{s5 General}}</h2>
 <ul>
   <li>{{s6 Follow the Mozilla Coding Style's <a href="https://developer.mozilla.org/en-US/docs/Developer_Guide/Coding_Style#General_C.2FC.2B.2B_Practices">general practices</a> and its <a href="https://developer.mozilla.org/en-US/docs/Developer_Guide/Coding_Style#Naming_and_Formatting_code">naming and formatting rules</a>.}}</li>
   <li>{{s8 All files should have a <a href="license-headers">license header</a>, but no mode line comments.}}</li>
   <li>{{s9 Newline at end of file, otherwise no trailing whitespace.}}</li>
   <li>{{s10 Lines can be longer than the limit, if limiting line length would hurt readability in a particular case.}}</li>
   <li>{{s11 Opening braces always go on their own line.}}</li>
   <li>{{s12 No hungarian notation, no special variable name prefixes or suffixes denoting type or scope. All variable names start with a lower case letter.}}</li>
   <li>{{s13 Don't comment code out, delete it.}}</li>
   <li>{{todo-comments Don't add TODO comments, create an <a href="https://issues.adblockplus.org">issue</a> and reference it in a comment instead.}}</li>
 </ul>
 
 <h2 id="javascript">{{s14 JavaScript}}</h2>
 <ul>
   <li>{{s15 Follow the Mozilla Coding Style's <a href="https://developer.mozilla.org/en-US/docs/Developer_Guide/Coding_Style#JavaScript_practices">JavaScript practices</a>.}}</li>
   <li>{{javascript-strict Always use <a href="https://developer.mozilla.org/docs/Web/JavaScript/Reference/Strict_mode">strict mode</a>.}}</li>
+  <li>{{javascript-operator-linebreak When splitting overlong expressions into multiple lines the joining binary operators should be left at the end of the line, before the linebreak. This does not apply to member access operators, such as <code><fix>.</fix></code> which should be placed on the following line.}}</li>
   <li>{{javascript-if-else-braces When an <code><fix>if</fix></code> statement, an <code><fix>else</fix></code> statement or a loop spans over more than one line always enclose it with braces.}}</li>
   <li>{{s18 In classes, prefix private functions with a single underscore to make them pseudo-private.}}</li>
   <li>{{javascript-spacing-literals Don't add any spaces immediately after opening, or before closing, an object or array literal.}}</li>
   <h3 id="javascript-modern">{{javascript-es6 Modern JavaScript (where supported)}}</h3>
   <ul>
     <li>{{javascript-block-scoping Always use <a href="https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/block#With_let_and_const">block-scoping</a> (<code><fix>let</fix></code> / <code><fix>const</fix></code>), except when sharing global variables between scripts cannot be avoided.}}</li>
     <li>{{javascript-const Use <code><fix>const</fix></code> for constant expressions that could as well have been inlined (e.g. static parameters, imported modules, etc.).}}</li>
     <li>{{javascript-arrow Use the <a href="https://developer.mozilla.org/docs/Web/JavaScript/Reference/Functions/Arrow_functions">arrow function</a> syntax when passing anonymous functions that don't require the binding of their own <code><fix>this</fix></code> or <code><fix>arguments</fix></code> variables.}}</li>
     <li>{{javascript-method Use the <a href="https://developer.mozilla.org/docs/Web/JavaScript/Reference/Functions/Method_definitions">method definition shorthand</a> syntax when defining methods on an object.}}</li>
     <li>{{javascript-for-of When iterating over arrays in the canonical order use the new <a href="https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/for...of"><code><fix>for..of</fix></code></a> syntax if the loop index isn't required. (Rather than using <code><fix>for(;;)</fix></code> or the <code><fix>forEach()</fix></code> method.)}}</li>
@@ skipping 48 matching lines @@
 <ul>
   <li>{{objc-conventions Follow Apple's <a href="https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/ProgrammingWithObjectiveC/Conventions/Conventions.html">conventions</a>}}.</li>
 </ul>
 
 <h2 id="puppet">{{s31 Puppet}}</h2>
 <ul>
   <li>{{s32 Follow the <a href="http://docs.puppetlabs.com/guides/style_guide.html">Puppet Style Guide</a>.}}</li>
   <li>{{s33 Opening braces don't go on their own line.}}</li>
   <li>{{s34 Arrows should not be aligned.}}</li>
 </ul>