Haskell infix operator for javascript

Question

Is there an equivalent construct in Javascript. If not, how would you create it?

Here is a simple explanation of what the infix operator does in Haskell:

What does the infix operator do in Haskell?

Answer 1

JavaScript does not have a list type, but Array s.

You can use...

 var newArr = [val].concat(arr); 

Alternatively, you can use unshift() to add to the array, but it modifies the original.

JavaScript does not have an operator : operator overloads or methods that look like operators, so you cannot get the same syntax as Haskell.

Answer 2

I saw that Leila Hamon is already linked to this article on emulating infix operators in JS .

But I thought an example might be useful to others.

Here's how you could hack Number and Boolean prototypes to handle seconded infix expressions like 4 < 5 < 10 .

You can expand this by adding more methods for more prototypes. This is a bit ugly, but can be useful in order to make queries less verbose.

 //Usage code (4) .gt (6) .gt (4) //false (100) .lt (200) .lt (400) . gt(0) . gt(-1)//true (100) [ '>' ] (50) [ '<' ] (20)//false //Setup Code (function(){ var lastVal = null; var nP = Number.prototype var bP = Boolean.prototype nP.gt = function(other){ lastVal = other; return this > other; } nP.lt = function(other){ lastVal = other; return this < other; } bP.gt = function(other){ var result = lastVal > other; lastVal = other; return result; } bP.lt = function(other){ var result = lastVal < other; lastVal = other; return result; } bP['<'] = bP.lt bP['>'] = bP.gt nP['<'] = nP.lt nP['>'] = nP.gt })() 

Answer 3

It is not the most beautiful, but it can help with readability in those places where you want infix so that your code reads like prose

 function nfx(firstArg, fn, secondArg){ return fn(firstArg, secondArg); } // Usage function plus(firstArg, secondArg) { return firstArg + secondArg; } nfx(1, plus, 2);