[Proposal] Array.prototype.includes should evaluate object.toString and/or object.valueOf when determining a match

[Mike Simon]

[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
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