Existential Operator / Null Propagation Operator
eli at eliperelman.com
Thu Oct 29 18:32:26 UTC 2015
2 dots may be problematic when parsing numbers (yeah, I know it's probably
not common, but it's still valid):
On Thu, Oct 29, 2015 at 1:29 PM, Sander Deryckere <sanderd17 at gmail.com>
> 2015-10-29 19:22 GMT+01:00 Laurentiu Macovei <alonecomp at gmail.com>:
>> This would be amazing operator!!
>> var error = a.b.c.d; //this would fail with error if a, b or c are null
>> or undefined.
>> var current = a && a.b && a.b.c && a.b.c.d; // the current messy way to
>> handle this
>> var typeScript = a?.b?.c?.d; // The typescript way of handling the above
>> mess with no errors
>> However I propose a more clear one - as not to confuse ? from the a ? b :
>> c statements with a?.b statements:
>> var x = a..b..c..d; //this would be ideal to understand that you assume
>> that if any of a, b, c is null or undefined the result will be null or
>> Two dots, means if its null or undefined stop processing further and
>> assume the result of expression is null or undefined. (as d would be null
>> or undefined).
>> Two dots make it more clear, more visible and more space-wise so you
>> understand what's going on.
>> What do you think folks?
> Do you also have a proposal on how to handle a["b"]["c"]["d"], so with
> possibly variable keys.
> In any case, I think that the existential operator (whatever the exact
> sign used is) will be better then the current way of chaining &&.
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> es-discuss at mozilla.org
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