Map/Set.prototype.size
+1
+1
Would .size be {[[Writable]]:false}?
let s = new Set([1,2,3,4]);
s.size; // 4
s.size = 1; // fail silently (loudly in strict mode)?
I swear there was some discussion either at an in-person on this list, but I'm having no luck tracking it down...
Rick Waldron wrote:
On Fri, Oct 12, 2012 at 11:43 AM, Erik Arvidsson <erik.arvidsson at gmail.com <mailto:erik.arvidsson at gmail.com>> wrote:
On Fri, Oct 12, 2012 at 11:41 AM, Rick Waldron <waldron.rick at gmail.com <mailto:waldron.rick at gmail.com>> wrote: > Would .size be {[[Writable]]:false}? It would be a getter on the prototype (and no setter)+1, That works for me.
+42.
+1
On Fri, Oct 12, 2012 at 11:16 AM, David Bruant <bruant.d at gmail.com> wrote:
Firefox has implement a Map/Set.prototype.size method to query the number of mapping/elements. It's not in the strawman. It appears in the latest draft, though weirdly enough Map.prototype.size is a function with an unused argument. What about making it an getter instead of a function? I guess we also don't need the extra parens to request for Map#keys, Map#values, Map#items.
For keys, values and items I think they are cleaner as methods since they return a new iterator every time.
If they were properties, I would expect the following to always be true:
map.items === map.items
On Fri, Oct 12, 2012 at 12:14 PM, Erik Arvidsson <erik.arvidsson at gmail.com> wrote:
On Fri, Oct 12, 2012 at 11:16 AM, David Bruant <bruant.d at gmail.com> wrote:
Firefox has implement a Map/Set.prototype.size method to query the number of mapping/elements. It's not in the strawman. It appears in the latest draft, though weirdly enough Map.prototype.size is a function with an unused argument. What about making it an getter instead of a function? I guess we also don't need the extra parens to request for Map#keys, Map#values, Map#items.
For keys, values and items I think they are cleaner as methods since they return a new iterator every time.
If they were properties, I would expect the following to always be true:
map.items === map.items
Agreed, I expect things that look like properties to be stable. Factories should be methods.
Erik Arvidsson wrote:
On Fri, Oct 12, 2012 at 11:16 AM, David Bruant<bruant.d at gmail.com> wrote:
Firefox has implement a Map/Set.prototype.size method to query the number of mapping/elements. It's not in the strawman. It appears in the latest draft, though weirdly enough Map.prototype.size is a function with an unused argument. What about making it an getter instead of a function? I guess we also don't need the extra parens to request for Map#keys, Map#values, Map#items.
For keys, values and items I think they are cleaner as methods since
+1
On Oct 12, 2012, at 12:14 PM, Erik Arvidsson <erik.arvidsson at gmail.com> wrote:
On Fri, Oct 12, 2012 at 11:16 AM, David Bruant <bruant.d at gmail.com> wrote:
Firefox has implement a Map/Set.prototype.size method to query the number of mapping/elements. It's not in the strawman. It appears in the latest draft, though weirdly enough Map.prototype.size is a function with an unused argument. What about making it an getter instead of a function? I guess we also don't need the extra parens to request for Map#keys, Map#values, Map#items.
For keys, values and items I think they are cleaner as methods since they return a new iterator every time.
Agreed.
Firefox has implement a Map/Set.prototype.size method to query the number of mapping/elements. It's not in the strawman. It appears in the latest draft, though weirdly enough Map.prototype.size is a function with an unused argument. What about making it an getter instead of a function? I guess we also don't need the extra parens to request for Map#keys, Map#values, Map#items.
Unlike Java, JavaScript is lucky enough to have getter/setters, we should use them, even in the spec. The boat for myArray.length has sunk a while ago, but new constructs can get this right.