Replace keyword with a javascript expression

Question

I have a string like hey! <input/>, Welcome in a template.

I need to replace every <input/> with the a JS expression this.input.

eg:

//Input
"hey! <input/>, Welcome";

Output should be:    
"hey! " + this.input + ", Welcome";

I can do a replace on the string with " + this.input + " but the problem is what if <input/> at the start or the end?

What is the best way to handle this?

Edit:

I don't want the output to be a string. I want the output to be a valid JS expression.

Valid inputs:
1) "hey! <input/>, Welcome";
2) "<input/>, Welcome";
3) "Welcome <input/>"

Outputs:
1) "hey! " + this.input + ", Welcome";
2) this.input + ", Welcome";
3) "Welcome " + this.input;

in a text editor? on a web form? where is the input coming from? — mr rogers
– mr rogers, Commented Jun 24, 2015 at 15:05
@anubhava this is not a duplicate of that question. I have to replace with a javascript expression. — Chirag Jain
– Chirag Jain, Commented Jun 24, 2015 at 15:07
@mrrogers This is in a template and i need to process such a string to output. — Chirag Jain
– Chirag Jain, Commented Jun 24, 2015 at 15:07
So like, "hey! <input/>, Welcome".replace(/<input\/>/g, '" + this.input + "'); will give you "hey! " + this.input + ", Welcome". Like that? — 1252748
– 1252748, Commented Jun 24, 2015 at 15:13
@thomas Yes like that. but the problem is what if <input/> is the first word in the string? — Chirag Jain
– Chirag Jain, Commented Jun 24, 2015 at 15:14

anubhava · Accepted Answer · 2015-06-24 20:26:40Z

1

As I wrote in comments above you can use:

var input = 'foo';
var str = "hey! <input/>, Welcome";
str = str.replace(/(.*?)<input\/>(.*)/, '$1' + this.input + '$2');

console.log(str);
//=> "hey! foo, Welcome"

edited Jun 24, 2015 at 20:26

answered Jun 24, 2015 at 16:49

anubhava

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2 Comments

Chirag Jain Over a year ago

Took the first valid input in the question and ran your code. Give me this: "hey! hey! <input/>, Welcome, Welcome

anubhava Over a year ago

That's not correct testing. I am just getting hey! undefined, Welcome" since this.input is undefined. Let me put full code for you.

Victor · Accepted Answer · 2015-06-24 15:20:11Z

0

"hey! <input/>, Welcome".replace(/<input\/>/, this.input);

EDIT:

John Reisig made a blog entry about making a minimal templating language parser in javascript. It's well written and may be a good starting point for your own templating language.

edited Jun 24, 2015 at 15:20

answered Jun 24, 2015 at 15:06

Victor

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4 Comments

Chirag Jain Over a year ago

I dont want the output to be a string like "hey this.input, Welcome.".

Chirag Jain Over a year ago

It should be a valid JS expression like "hey, " + this.input + ", Welcome"

Victor Over a year ago

Is input just a placeholder variable?

Chirag Jain Over a year ago

yes. replace the placeholder to create a valid js expression.

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