Adding method to a method

Question

I want my code to be like this:

select("*").where("you='me'").and("me='him'").and("game='nes'");

I have only this:

function select(selector){
 this.where = function(where){
 //Do something with where and select.
 //Add the method AND <---
 }
}

I dont know how to add the method add in the method where.

• Anthony Forloney: What it seems you are trying to achieve is calling method chaining, read a bit here: kwilson.me.uk/blog/simple-javascript-method-chaining

Answer 1

This is sometimes called a 'fluent interface'

Simply return this from each function.

If you want to capture the "select" context, capture this in a variable within that scope and then return it when needed. This is important as this points at the function that is currently executing.

function select(s){
 var that = this;
 this.where = function(condition){
 that.filter(condition);
 return that; //this == select.where
 }
 this.and = function (condition) {
 that.filter(condition);
 return that;
 }
 this.end = function(){
 return that.results(); // or similar depending on the consumed api of course
 }
 return this; // this == select
}

• Federico Piragua: Yeah it works! I will check you but I think there is a different method, like jQuery's, but thanks, I appreciate it!

Answer 2

In each function, put "return this;" at the bottom. So when you call .and() it's called on "this", which is "select". Sorry on iPhone, so no formatting!

Answer 3

one way to do it:

function select(selector){
 return {where:function(where){
 //do whatever you're doing with where and selector
 return {and:function(whatever){/*do something with whatever*/}}
 }}
}

you can add additional functions to each returned object

Jsfiddle: http://jsfiddle.net/markasoftware/78aSa/1/

if you are trying to make it so that and and where are on the same object, do this instead:

function select(selector){
 var selectObj=this;
 this.where=function(where){
 //do whatever with where and select
 //now add the and method
 selectObj.and=function(whatever){
 //do stuff with selector, where, and whatever
 }
 return selectObj
 }
 return selectObj;
}

jsfiddle of this one: http://jsfiddle.net/markasoftware/34BYa/