CKBuilder fails on ES6 Promises

[Karen Ananiev]

.catch() in ES6 Promises causes an CKBuilder error:

Jun 25, 2015 8:39:12 PM com.google.javascript.jscomp.LoggerErrorManager println
SEVERE: plugin.js:87: ERROR - Parse error. missing name after . operator
                                }).catch(function() {
                                         ^

[Piotrek Koszuliński]

Confirmed. AFAIK GCC should be executed with flag allowing ES5. In ES3 catch was a reserved keyword, so this is why this code fails. But the reason why we use GCC in ES3 mode is to catch cases like trailing commas which would crash editor in IE Quirks Mode and Compat Mode. Perhaps a solution here would be to expose this setting in CKBuilder.

[Wiktor Walc]

Just to make it clear: it should be possible to configure CKBuilder (by adding a command line flag) to use ES3, ES5 or ES6.