Xavier MONTILLET wrote:
Here's an example:
var array = [ { v: 3.2 }, { v: 1.3 }, { v: 2.1 } ];
var compare = function ( a, b ) {
return a - b;
};
var transform = function ( x ) {
return { v: x.v - Math.floor( x.v ) };
};
var sortedArray = array.sort( compare, transform );
console.log( array.map( transform ) );// [ { v: .2 }, { v: .3 }, { v:
.1 } ]
// you can see to sort it you need to take the last element and put it
at the beginning
// so you do that on array:
console.log( sortedArray );// [ { v: 2.1 }, {v: 3.2 }, {v: 1.3 } ]
So you sort the transformed array and you apply the exact same
modifications to the original .
Is it clearer?
Yes, clear enough -- however adding new trailing arguments to an
existing method is treacherous. It's likely calls in the wild pass a
second argument by mistake. Less likely but still possible: an
implementation has unwisely extended sort to have an optional second
parameter already. This goes against the now-explicit NOTE in ES5:
NOTE Implementations that add additional capabilities to the set of
built-in functions are encouraged to do so by adding new functions
rather than adding new parameters to existing functions.
We could rule this out for the top five browser engines, but the
possibility of extant code passing an extra actual parameter remains.
Better to have a new sortWithTransform method if necessary.
/be
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