current community

your communities

more stack exchange communities

company blog
Stack Exchange Inbox Reputation and Badges
tour help
stack overflow careers
Sign up ×
Stack Overflow is a question and answer site for professional and enthusiast programmers. It's 100% free.
up vote 0 down vote favorite

I have such template "text %variable.key% text". The variable.key is the variable. And I need to rename such variables to "text "+variable.key+" text", to make them work.

I have tried to do something like this:

var tpl = "text %variable.key% text";
tpl = tpl.replace(/%(.*?)%/, function(a,b) {
    return eval('b');
});

but it also returns a string.

Can somebody tell me how to do this?

share|improve this question
5  
fyi, eval is strongly discouraged. –  Daniel A. White Sep 19 '12 at 12:05
1  
Besides the evilness of eval, I think you meant to use eval(b) –  Alexander Sep 19 '12 at 12:07
    
in addition to Daniel White's comment: try searching for [js] eval evil on SO if you want to know more. –  11684 Sep 19 '12 at 12:08
    
Thank you for inform me. I didn't knew it –  Nikita Gavrilov Sep 19 '12 at 12:08

4 Answers 4

up vote 2 down vote accepted

It's easy to do without using eval at all:

function getValue(path) {
    var target = this;
    path.split('.').forEach(function (branch) {
        if (typeof target === "undefined") return;
        target = (typeof target[branch] === "undefined") ? undefined : target[branch];
    });

    return target;
}

If you want to get properties starting from window you can just call getValue("path.to.property"). If you want to start from some other root object, use getValue.call(rootObject, "path.to.property").

The function could also be adapted to take the root object as an optional first parameter, but the idea remains the same.

See it in action.

Important: This will not work on Internet Explorer < 9 because Array.prototype.forEach will not exist. You can fix that with

if (!Array.prototype.forEach) {
    Array.prototype.forEach = function(fun /*, thisPointer */) {
        var len = this.length;
        if (typeof fun != "function") throw new TypeError();

        var thisPointer = arguments[1];
        for (var i = 0; i < len; i++) {
            if (i in this) {
                fun.call(thisPointer, this[i], i, this);
            }
        }
    };
}
share|improve this answer
    
After all, there is a big hemorrhoid with the window[b]. So I will use your solution. Thank you! –  Nikita Gavrilov Sep 19 '12 at 12:33
up vote 1 down vote 
var tpl = "text %variable.key% text";
tpl = tpl.replace(/%(.*?)%/, function(a,b) {
    return eval(b);// remove quote.
});

jsfiddle

share|improve this answer
    
yeap, it's realy works. Thanks. But is there any other possibility to do the same but with no eval? –  Nikita Gavrilov Sep 19 '12 at 12:11
up vote 1 down vote

Your code is correct but you need to eval b, not 'b':

var tpl = "text %variable.key% text";
tpl = tpl.replace(/%(.*?)%/, function(a,b) {
    return eval(b);
});

As was mentioned in the comments, using eval is not the way to go. You could get the variable value like this as wel:

var tpl = "text %variable.key% text";
tpl = tpl.replace(/%(.*?)%/, function(a,b) {
    return window[b];
});

DEMO

share|improve this answer
up vote 1 down vote

Another variant, without eval() , works with simple variable, or object:

var var_name = 'value';

// object
var obj = new Object();
 obj.prop = 'some val';

var tpl = "text %obj.prop% text %var_name% text";
tpl = tpl.replace(/%(.*?)%/gi, function(a,b) {
  var iv = b.split('.');
  return (iv.length == 2) ? window[iv[0]][iv[1]] : window[iv[0]];
});

// test
alert(tpl);
share|improve this answer
    
Thank you! I think this is the best solution! thank you again! –  Nikita Gavrilov Sep 19 '12 at 12:20
    
Just a little fix for objects should be added –  Nikita Gavrilov Sep 19 '12 at 12:22

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.