Javascript add string to start

Question

my code:

var test = "aa";
test += "ee";
alert(test);

Prints out "aaee"

How can I do the same thing, but add the string not to end, but start: Like this:

var test = "aa";
test = "ee" + test;

This is the long way, but is there somekind of shorter way like in 1st example?

What I want is that I must not write the initial variable out again in definition.

Your two code samples are not the same. The first yields "aaee" the second "eeaa"; — The Internet
– The Internet, Commented Aug 23, 2012 at 6:46
jQuery offers a .prepend() function. In pure JS I would just do test += "ee"; Also, why do you want to do this? — The Internet
– The Internet, Commented Aug 23, 2012 at 6:48

Darin Dimitrov · Accepted Answer · 2012-08-23 06:48:32Z

9

There's no built-in operator that allows you to achieve this as in the first example. Also test = "ee" + test; seems pretty self explanatory.

answered Aug 23, 2012 at 6:48

Darin Dimitrov

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Comments

Gaurav Lad · Accepted Answer · 2016-04-21 05:36:12Z

4

You could do it this way ..

test = test.replace (/^/,'ee');

disclaimer: http://xkcd.com/208/

Wait, forgot to escape a space. Wheeeeee[taptaptap]eeeeee.

answered Apr 21, 2016 at 5:36

Gaurav Lad

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Comments

Torsten Walter · Accepted Answer · 2012-08-23 06:53:41Z

1

You have a few possibilities although not a really short one:

var test = "aa";

// all yield eeaa
result = "ee" + test;
result = test.replace(/^/, "ee");

answered Aug 23, 2012 at 6:53

Torsten Walter

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Dr. Dan · Accepted Answer · 2012-08-23 06:49:13Z

0

var test = "aa";
 alert('ee'.concat(test));

answered Aug 23, 2012 at 6:49

Dr. Dan

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1 Comment

Jaanus Over a year ago

isn't test = "ee" + test; shorter?

painotpi · Accepted Answer · 2012-08-23 06:57:13Z

0

What you have, test = "ee" + test; seems completely fine, and there's no shorter way to do this.

If you want a js solution on this you can do something like,

test = test.replace(/^/, "ee");

There are a whole lot of ways you can achieve this, but test = "ee" + test; seems the best imo.

answered Aug 23, 2012 at 6:57

painotpi

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Comments

Vega · Accepted Answer · 2021-06-20 13:01:13Z

0

You can add a string at the start (multiple times, if needed) until the resulting string reaches the length you want with String.prototype.padStart(). like this:

var test = "aa";
test = test.padStart(4, "e");
alert(test);

Prints out

eeaa

var test = "aa";
test = test.padStart(5, "e");
alert(test);

Prints out

eeeaa

edited Jun 20, 2021 at 13:01

Vega

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answered Jun 20, 2021 at 11:07

Gustavo Martínez

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