Format a JavaScript string using placeholders and an object of substitutions?

Question

I have a string with say: My Name is %NAME% and my age is %AGE%.

%XXX% are placeholders. We need to substitute values there from an object.

Answer 1

You can use a custom replace function like this:

var str = "My Name is %NAME% and my age is %AGE%.";
var replaceData = {"%NAME%":"Mike","%AGE%":"26","%EVENT%":"20"};

function substitute(str, data) {
    var output = str.replace(/%[^%]+%/g, function(match) {
        if (match in data) {
            return(data[match]);
        } else {
            return("");
        }
    });
    return(output);
}

var output = substitute(str, replaceData);

You can see it work here: http://jsfiddle.net/jfriend00/DyCwk/.