How create dynamically function in javascript?

Question

I want to create some functions dynamically with javascript. all function do special work, but with different data(for example, console.log("data")).

config = ['data1', 'data2', 'data3'];
returned = {};
for(var i in config){
    returned[config[i]] = function(){console.log(config[i])};
}

I above code, All functions must log a data, but different data. I want to when I call returned["data1"]() it log data1, But when I call returned["data1"]() it log data3.

Is it possible? How can I do?

This is because objects are reference typed variable and it will hod reference of last value. You will have to bind each function with specific value — Rajesh, Nov 25 '15 at 17:59

score 2 · Answer 1 · answered Nov 25 '15 at 18:00

2

This is probably what you are looking for.

var returned = {};
['data1', 'data2', 'data3'].forEach(function(element) { 
  returned[element] = function() { console.log(element); };
});

answered Nov 25 '15 at 18:00

NMunro

890
5
20

27 sec difference... – rodrigo-silveira Nov 25 '15 at 18:01
Haha, sorry dude! Great minds though. – NMunro Nov 25 '15 at 18:03

rodrigo-silveira · Accepted Answer · 2015-11-25T18:08:20.040

config = ['data1', 'data2', 'data3'];
returned = {};
config.forEach(function(data){
    returned[data] = function(){
       console.log(data);
    };
});

Edit

You could also extract that inner function so it's slightly more memory efficient:

config = ['data1', 'data2', 'data3'];
returned = {};

function doSpecialWork(data){
    console.log(data);
};

config.forEach(function(data){
    returned[data] = doSpecialWork(data);
});

Edit 2

You could also get silly, but call yourself functional:

config = ['data1', 'data2', 'data3'];

function doSpecialWork(data){
    console.log(data);
};

returned = config.reduce(function(returned, data){
    returned[data] = doSpecialWork(data);

    return returned;
}, {});

How create dynamically function in javascript?

2 Answers2