2.2.0

[GeoffreyBooth]

This release fixes all currently open bugs, dating as far back as 2014, 2012 and 2011. Heartfelt thanks and congratulations to @zdenko!

• Potential breaking change: An inline if or switch statement with an ambiguous else, such as if no then if yes then alert 1 else alert 2, now compiles where the else always corresponds to the closest open then. Previously the behavior of an ambiguous else was unpredictable. If your code has any if … then or switch … then statements with multiple thens (and one or more elses) the compiled output might be different now, unless you had resolved ambiguity via parentheses. We made this change because the previous behavior was inconsistent and basically a bug: depending on what grammar was where, for example if there was an inline function or something that implied a block, the else might bind to an earlier then rather than a later then. Now an else essentially closes a block opened by a then, similar to closing an open parenthesis. Fix #3921 & #2342: inline function without parentheses used in condition, inline 'else' #4838
• When a required then is missing, the error more accurately points out the location of the mistake. Fix #3933: Missing then doesn’t trigger nearby error #4862, Fix #4871: else if no longer output together #4872
• An error is thrown when the coffee command is run in an environment that doesn’t support some ES2015 JavaScript features that the CoffeeScript compiler itself requires. This can happen if CoffeeScript is installed in Node older than version 6. Throw warning for unsupported runtimes, e.g. Node < 6 #4839
• Destructuring with a non-final splat/spread, e.g. [open, contents..., close] = tag.split('') is now output using ES2015 rest syntax. [Change]: Destructuring with non-final spread should still use rest syntax (#4517) #4825
• Functions named get or set can be used without parentheses in more cases, including when attached to this or @ or ?.; or when the first argument is an implicit object, e.g. @set key: 'val'. Fix #4836: functions named get or set can be used without parentheses when attached to @ #4837, Fix #4852, @get @set implicit object #4867
• Statements such as break can now be used inside parentheses, e.g. (doSomething(); break) while condition or (pick(key); break) for key of obj. Fix #3441: parentheses wrapping expression throw invalid error  #4849
• Bugfix for assigning to a property attached to this/@ in destructuring, e.g. ({@prop = yes, @otherProp = no}) ->. Fix #4843: bad output when assigning to @prop in destructuring assignment with defaults #4848
• Bugfix for incorrect errors being thrown about calling super with a parameter attached to this when said parameter is in a lower scope, e.g. class Child extends Parent then constructor: -> super(-> @prop). Fix #4868: Incorrect ‘Can’t call super with @params’ error #4869
• Bugfix to prevent a possible infinite loop when a for loop is given a variable to step by, e.g. for x in [1..3] by step (as opposed to by 0.5 or some other primitive numeric value). Fix #2047: Infinite loop possible when for loop with range uses variables #4853
• Bugfix to no longer declare iterator variables twice when evaluating a range, e.g. end = 3; fn [0..end]. Fix #4105: Duplicate variable i defined when evaluating range #4855
• Bugfix for incorrect scope of variables in chained calls, e.g. start(x = 3).then(-> x = 4). Fix #4437: variable scope in chained calls #4863
• Bugfix for incorrect scope of variables in a function passed to do, e.g. for [1..3] then masked = 10; do -> alert masked. Fix #1403: Variables inconsistently masked inside of do #4854
• Bugfix to no longer throw a syntax error for a trailing comma in a function call, e.g. fn arg1, arg2,. Fix #3306: trailing comma in a function call in the last line throws a syntax error #4860
• Bugfix for an expression in a property access, e.g. a[!b in c..]. Fix #1726: expression in property access causes unexpected results #4851
• Bugfix to allow a line continuation backslash (\) at any point in a for line. Fix #3909: Backslash to break line is inconsistent in 'for ... of' and 'for ... in' loops #4861

http://rawgit.com/GeoffreyBooth/coffeescript/2.2.0/docs/v2/#changelog
@jashkenas @lydell @connec

[jashkenas]

I speak from the bottom of my heart, when I say: Holy crap!

Three cheers for @zdenko!

[GeoffreyBooth]

This is also our 1,000th closed pull request! 🎆