javascript - Create a prototype method that works alone but can also have sub-methods -

i don't know how else name title, sorry.

here example, want able this:

var str = 'bla bla bla';  str.do(a).thendo(b)   //but want able this: str.do(a) // different  // have tried doesn't work: string.prototype.do = function(a) {   //here code 'str' variable, then:   var self = {};   self.thendo = function(b) {     var somecalculations;     return somecalculations + + b;   }   self = function() {     //this supposed do(a) function     var morecalculations;     return morecalculations + a;   }   return self; } 

note: thendo() needs use 'a' parameter do() not in i'm trying achieve:

string.prototype.do = function(a) {    var morecalculations;    return morecalculations + a; } string.prototype.do.thendo = function(b) {    var somecalculations;    return somecalculations + + b; } //it doesnt work, thendo() cant 'a' parameter 

furthermore need library i'm developing jquery answers not help.

thanks

you've said:

str.do(a).thendo(b)   //but want able this: str.do(a) // different 

it's impossible do(a) part of different depending on whether return value used. e.g., do(a) part of str.do(a) , str.do(a).thendo(b) cannot know it's meant different in 2 cases. doesn't have information (which thing™).

you make work:

str.do(a)();           // 1 thing str.do(a).thendo(b);   // else 

note () @ end of first one. that's trigger lets differentiate 2 cases:

(function() {    function string$do(v1) {      // function called if caller uses () on result      function immediate() {        console.log("something: ", v1);      }      // called if use .thendo() instead      immediate.thendo = function(v2) {        console.log("something else: ", 1, v2);      };      return immediate;    }    object.defineproperty(string.prototype, "do", {      value: string$do    });  })();    var str = "testing 1 2 3";  str.do(42)();  str.do(42).thendo(67);

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side note: when extending built-in prototypes (which many advocate against), always sure use object.defineproperty or object.defineproperties , use default enumerable flag (or explicitly set false) don't create enumerable property. won't naming conflicts, may code naively assuming default set of built-in prototype properties in for-in loops, in checks, etc.