How can I pass a reference to a function with parameters

Question

Possible Duplicate    How can I pre-set arguments in JavaScript function call   Partial Function Application        I need to able to pass a reference to a function with a given set of parameters   Here is an example of passing a reference without parameters   var f   function            Some logic here        var fr   f    Here I am passing a reference to function  f   without parameters fr      the  f  function is invoked  without parameters   Now what I need to do is pass the same f function  but this time I would need to pass parameters to the reference   Now  I can do it with an anonymous function and invoke the f function with parameters inside the newly created function  like such   var f   function                Some logic here            var fr   function  pars        f pars        Here I am creating an anonymous function  and invoking f inside it  fr  p    a parameter       Invoking the fr function  that will later invoke the f function with parameters   But my question is  Is there a way to pass a direct reference to the f function With parameters to fr  but without enclosing it in an anonymous function   What do I need to assign to fr to make it invokable without parameters  fr     so that f 1 2 3  is executed when fr is invoked       UPDATE   I followed Jason Bunting s answer to here about the Partial Function and the JavaScript function he posts there is exactly what I was looking for   Here is the solution   function partial func     0  n args         var args   Array prototype slice call arguments  splice 1     return function         var allArguments   args concat Array prototype slice call arguments        return func apply this  allArguments

User · Answer

The following is equivalent to your second code block:

var f = function () {
        //Some logic here...
    };

var fr = f;

fr(pars);

If you want to actually pass a reference to a function to some other function, you can do something like this:

function fiz(x, y, z) {
    return x + y + z;
}

// elsewhere...

function foo(fn, p, q, r) {
    return function () {
        return fn(p, q, r);
    }
}

// finally...

f = foo(fiz, 1, 2, 3);
f(); // returns 6

You're almost certainly better off using a framework for this sort of thing, though.

User · Answer

What you are after is called partial function application    Don t be fooled by those that don t understand the subtle difference between that and currying  they are different   Partial function application can be used to implement  but is not currying  Here is a quote from a blog post on the difference      Where partial application takes a function and from it builds a function which takes fewer arguments  currying builds functions which take multiple arguments by composition of functions which each take a single argument    This has already been answered  see this question for your answer  How can I pre-set arguments in JavaScript function call   Example   var fr   partial f  1  2  3       now  when you invoke fr   it will invoke f 1 2 3  fr      Again  see that question for the details

User · Answer

The following is equivalent to your second code block:

var f = function () {
        //Some logic here...
    };

var fr = f;

fr(pars);

If you want to actually pass a reference to a function to some other function, you can do something like this:

function fiz(x, y, z) {
    return x + y + z;
}

// elsewhere...

function foo(fn, p, q, r) {
    return function () {
        return fn(p, q, r);
    }
}

// finally...

f = foo(fiz, 1, 2, 3);
f(); // returns 6

You're almost certainly better off using a framework for this sort of thing, though.

User · Answer

The following is equivalent to your second code block:

var f = function () {
        //Some logic here...
    };

var fr = f;

fr(pars);

If you want to actually pass a reference to a function to some other function, you can do something like this:

function fiz(x, y, z) {
    return x + y + z;
}

// elsewhere...

function foo(fn, p, q, r) {
    return function () {
        return fn(p, q, r);
    }
}

// finally...

f = foo(fiz, 1, 2, 3);
f(); // returns 6

You're almost certainly better off using a framework for this sort of thing, though.

User · Answer

What you are after is called partial function application    Don t be fooled by those that don t understand the subtle difference between that and currying  they are different   Partial function application can be used to implement  but is not currying  Here is a quote from a blog post on the difference      Where partial application takes a function and from it builds a function which takes fewer arguments  currying builds functions which take multiple arguments by composition of functions which each take a single argument    This has already been answered  see this question for your answer  How can I pre-set arguments in JavaScript function call   Example   var fr   partial f  1  2  3       now  when you invoke fr   it will invoke f 1 2 3  fr      Again  see that question for the details

User · Answer

You can also overload the Function prototype      partially applies the specified arguments to a function  returning a new function Function prototype curry   function          var func   this      var slice   Array prototype slice      var appliedArgs   slice call  arguments  0         return function              var leftoverArgs   slice call  arguments  0            return func apply  this  appliedArgs concat  leftoverArgs                    can do other fancy things      flips the first two arguments of a function Function prototype flip   function          var func   this      return function              var first   arguments 0           var second   arguments 1           var rest   Array prototype slice call  arguments  2            var newArgs    second  first  concat  rest             return func apply  this  newArgs                  e g   var foo   function  a  b  c  d     console log  a  b  c  d      var iAmA   foo curry   I    am    a     iAmA   Donkey     - gt  I am a Donkey  var bah   foo flip     bah  1  2  3  4    - gt  2 1 3 4

User · Answer

You can also overload the Function prototype      partially applies the specified arguments to a function  returning a new function Function prototype curry   function          var func   this      var slice   Array prototype slice      var appliedArgs   slice call  arguments  0         return function              var leftoverArgs   slice call  arguments  0            return func apply  this  appliedArgs concat  leftoverArgs                    can do other fancy things      flips the first two arguments of a function Function prototype flip   function          var func   this      return function              var first   arguments 0           var second   arguments 1           var rest   Array prototype slice call  arguments  2            var newArgs    second  first  concat  rest             return func apply  this  newArgs                  e g   var foo   function  a  b  c  d     console log  a  b  c  d      var iAmA   foo curry   I    am    a     iAmA   Donkey     - gt  I am a Donkey  var bah   foo flip     bah  1  2  3  4    - gt  2 1 3 4

User · Answer

What you are after is called partial function application    Don t be fooled by those that don t understand the subtle difference between that and currying  they are different   Partial function application can be used to implement  but is not currying  Here is a quote from a blog post on the difference      Where partial application takes a function and from it builds a function which takes fewer arguments  currying builds functions which take multiple arguments by composition of functions which each take a single argument    This has already been answered  see this question for your answer  How can I pre-set arguments in JavaScript function call   Example   var fr   partial f  1  2  3       now  when you invoke fr   it will invoke f 1 2 3  fr      Again  see that question for the details

User · Answer

The following is equivalent to your second code block:

var f = function () {
        //Some logic here...
    };

var fr = f;

fr(pars);

If you want to actually pass a reference to a function to some other function, you can do something like this:

function fiz(x, y, z) {
    return x + y + z;
}

// elsewhere...

function foo(fn, p, q, r) {
    return function () {
        return fn(p, q, r);
    }
}

// finally...

f = foo(fiz, 1, 2, 3);
f(); // returns 6

You're almost certainly better off using a framework for this sort of thing, though.

User · Answer

What you are after is called partial function application    Don t be fooled by those that don t understand the subtle difference between that and currying  they are different   Partial function application can be used to implement  but is not currying  Here is a quote from a blog post on the difference      Where partial application takes a function and from it builds a function which takes fewer arguments  currying builds functions which take multiple arguments by composition of functions which each take a single argument    This has already been answered  see this question for your answer  How can I pre-set arguments in JavaScript function call   Example   var fr   partial f  1  2  3       now  when you invoke fr   it will invoke f 1 2 3  fr      Again  see that question for the details

[javascript] How can I pass a reference to a function, with parameters?

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