Guide to organizing a collection of functions within a Javascript namespace script

Question

Guide to organizing a collection of functions within a Javascript namespace script

I'm currently working on implementing an array of functions into my script. When I utilize namespacing objects and this array, all the functions end up being labeled as undefined.

How can I construct this array in a way that ensures proper function references for processing processAllFunction?

Take a look at my code:


var myns = myns || {};
myns.test = myns.test || {};
myns.test.util = {
    myOne: function(m) {
        return m;
    },
    myTwo: function(m) {
        return m;
    },
    processAllFunction: function(m) {
        for(var i=0; i<this.replaceFilters.length; i++) {
            if(typeof(this.replaceFilters[i])==='function') {
                m= this.replaceFilters[i](m);
            }
        }
        console.log(this.replaceFilters); // undefined functions
        return m;
    },
    replaceFilters: [this.myOne, this.myTwo]
};

javascript arrays namespaces function-pointers undefined

Answer 1

Answer №1

When looking at your code, the keyword this can either point to the global object window, or to the context of the function where myns is defined - hence why you are encountering an issue with undefined. To resolve this, you need a reference to the object that called the method. You can achieve this by making some adjustments:


var myns = myns || {};
myns.test = myns.test || {};
myns.test.util = {
    myOne: function(m) {
        return m;
    },
    myTwo: function(m) {
        return m;
    },
    processAllFunction: function(m) {
        for(var i = 0; i < this.getReplaceFilters().length; i++) {
            if(typeof(this.getReplaceFilters()[i]) === 'function') {
               m= this.replaceFilters[i](m);
            }
        }
        return m;
    },
    getReplaceFilters: function() {
        return [this.myOne, this.myTwo];
    }    
};

The major change is seen in the definition of getReplaceFilters where instead of directly assigning [this.myOne, this.myTwo] to replaceFilters, it is now a function that returns the array. By doing so, whenever you call

myns.test.util.getReplaceFilters()

, this will refer to myns.test.util. This same concept applies when calling

myns.test.util.processAllFunction()

; this is consistently set to myns.test.util. The value of this in these scenarios is also utilized in the invocation of getReplaceFilters within processAllFunction.

Answer 2

When looking at your code, the keyword this can either point to the global object window, or to the context of the function where myns is defined - hence why you are encountering an issue with undefined. To resolve this, you need a reference to the object that called the method. You can achieve this by making some adjustments:


var myns = myns || {};
myns.test = myns.test || {};
myns.test.util = {
    myOne: function(m) {
        return m;
    },
    myTwo: function(m) {
        return m;
    },
    processAllFunction: function(m) {
        for(var i = 0; i < this.getReplaceFilters().length; i++) {
            if(typeof(this.getReplaceFilters()[i]) === 'function') {
               m= this.replaceFilters[i](m);
            }
        }
        return m;
    },
    getReplaceFilters: function() {
        return [this.myOne, this.myTwo];
    }    
};

The major change is seen in the definition of getReplaceFilters where instead of directly assigning [this.myOne, this.myTwo] to replaceFilters, it is now a function that returns the array. By doing so, whenever you call

myns.test.util.getReplaceFilters()

, this will refer to myns.test.util. This same concept applies when calling

myns.test.util.processAllFunction()

; this is consistently set to myns.test.util. The value of this in these scenarios is also utilized in the invocation of getReplaceFilters within processAllFunction.

Answer 3

Answer №2

Here is a helpful tip: move the replaceFilters function outside of the object after declaring it.

myns.test.util = {
    myOne: function(m) {
        return m;
    },
    myTwo: function(m) {
        return m;
    },
    processAllFunction: function(m) {
        for(var i=0; i<this.replaceFilters.length; i++) {
            if(typeof(this.replaceFilters[i])==='function') {
                m = this.replaceFilters[i](m);
            }
        }
        console.log(this.replaceFilters);
        return m;
    }
};
myns.test.util.replaceFilters = [this.myOne, this.myTwo];

By using this approach, you can avoid any issues with this.

Answer 4

Here is a helpful tip: move the replaceFilters function outside of the object after declaring it.

myns.test.util = {
    myOne: function(m) {
        return m;
    },
    myTwo: function(m) {
        return m;
    },
    processAllFunction: function(m) {
        for(var i=0; i<this.replaceFilters.length; i++) {
            if(typeof(this.replaceFilters[i])==='function') {
                m = this.replaceFilters[i](m);
            }
        }
        console.log(this.replaceFilters);
        return m;
    }
};
myns.test.util.replaceFilters = [this.myOne, this.myTwo];

By using this approach, you can avoid any issues with this.

Guide to organizing a collection of functions within a Javascript namespace script

Answer №1

Answer №2

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