Question

I’m not sure exactly how the final implementation will be, but the basics are to insert method arguments into a string “template”. The first instance, I could just do a regex replace but that has some downfalls, which I’m willing to accept if necessary. The second one is a bit more difficult. How can I get the names from the template and replace with matched from the passed object? Thanks for any help.

var myTemplate = 'Hello {name}'; // or something similar
var name = 'Bob';
function applyTemplate(tpl,str) {
    //do stuff here to replace {name} with passed argument
}
var newStr = applyTemplate(myTemplate,name); //should return 'Hello Bob'

//Also this one
var myTemplate = 'Good {timeOfDay} {name}';

function applyTemplate(tpl,o) {
    //simple objects only, don't need nested
}
var newStr = applyTemplate(myTemplate,{name:'Bob',timeOfDay:'morning'}); //should return 'Good morning Bob'

Answer 1

If you don’t need extra checking&validation, you could just replace the {key} with the value such as :

function applyTemplate(tpl,o) {
    for(var key in o)
        {
            if(o.hasOwnProperty(key))// prevent iteration on any prototype inherited methods
                tpl = tpl.replace('{'+key+'}',o[key]);
        }
    return tpl;
}

As for your simple first applyTemplate function, since you do not have any notion about what the key should be, you can use regex to replaceonly the first {...} encountered :

 function applyTemplate(tpl,str) {
     return tpl.replace(/{.*?}/,str);
}

And then, of course , you can combine these two functions in one, with slightly different functionalities based on the type of the arguments:

 function applyTemplate(tpl,o) {
    switch(typeof o){
        case 'object' : 
            for(var key in o)
                {
                    if(o.hasOwnProperty(key))
                        tpl = tpl.replace('{'+key+'}',o[key]);
                }
            break;
        case 'string' : 
           tpl = tpl.replace(/{.*?}/,o);
           break;
        default : 
            throw new Error('no valid parameters supplied');
    }
    return tpl;
}

This should do the trick. If you are interested, you could take a peak at the jquery template system : http://api.jquery.com/jQuery.template/.

Hope this helped.