nixkuroi at gmail.com (2018-06-20T18:57:16.050Z)
True, there are many other ways to make this work. You could even use filter(function(f){f.name==‘abc’;}).length > 0 .
The focus of this proposal is that the purpose of .valueOf and .toString are to allow for objects to return a default value without requiring the matching method to know about the contents or property names of any object.
Array.prototype.some, and any method mentioned above, require a that a content aware function be passed in to facilitate the match. This proposal mitigates that, and allows Array.prototype.includes to evaluate the object as the object design was intended.
True, there are many other ways to make this work. You could even use filter(function(f){f.name==‘abc’;}).length > 0 . The focus of this proposal is that the purpose of .valueOf and .toString are to allow for objects to return a default value without requiring the matching method to know about the contents or property names of any of next. Array.prototype.some, and any method mentioned above require a that a content aware function be passed in to facilitate the match. This proposal mitigates that, and allows Array.prototype.includes to evaluate the object as the object design was intended. > On Jun 20, 2018, at 11:33 AM, Andrea <andrea.giammarchi at gmail.com> wrote: > > It looks like you want included to use `==` for comparison, opening a whole new world of issues. > > You have `some` and your code to do that with ease, same goes for `find` or `findIndex`, very appropriate for this use case. > > ```js > items.some(o => o == 'abc'); > ``` > > Regards > >> On Wed, Jun 20, 2018 at 8:27 PM, Mike Simon <nixkuroi at gmail.com> wrote: >> [Proposal] Array.prototype.includes should evaluate object.toString and/or object.valueOf when determining a match >> >> The problem: >> >> If I have a list of objects that contain a toString() prototype that returns a value from the object, Array.prototype.includes does not return true if the value/string returned from the object is a match for the parameter value. >> >> Test code: >> >> var thingy = function(name) {this.name=name;}; >> thingy.prototype.valueOf = function(){return this.name}; >> thingy.prototype.toString = function(){return this.name}; >> var items = [new thingy('abc'),new thingy('def')]; >> var inc = items.includes('abc'); >> alert(items[0]); // alerts abc >> alert(inc); // returns false >> >> While it’s possible to create this as a list of strings using map, this would seem to conserve memory, as well as reduce the complexity of the code to perform this operation. >> >> Link: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes >> >> _______________________________________________ >> es-discuss mailing list >> es-discuss at mozilla.org >> https://mail.mozilla.org/listinfo/es-discuss >> > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20180620/de0f33dc/attachment.html>