I have a string in Javascript that contains variables with the format ${var-name}. For example:

'This is a string with ${var1} and ${var2}'

I need to get these variables in an array: ['var1','var2'].

Is this possible with regex?

I have a string in Javascript that contains variables with the format ${var-name}. For example:

'This is a string with ${var1} and ${var2}'

I need to get these variables in an array: ['var1','var2'].

Is this possible with regex?

• javascript
• regex

• this gives [ "${var1}", "${var2}" ] – atmd Commented Apr 10, 2015 at 12:12
• Do you need array of variables or array of names of variables, mentioned in the string? – Ruben Kazumov Commented Apr 10, 2015 at 12:12
• see my example, array of variable names – ps0604 Commented Apr 10, 2015 at 12:15

3 Answers 3

Have a try with:

/\$\{(\w+?)\}/

Running example, many thanks to @RGraham :

var regex = new RegExp(/\$\{(\w+?)\}/g),
    text = "This is a string with ${var1} and ${var2} and {var3}",
    result,
    out = [];
while(result = regex.exec(text)) {
    out.push(result[1]);
}
console.log(out);

This regex - \${([^\s}]+)(?=}) - should work.

Explanation:

• \${ - Match literal ${
• ([^\s}]+) - A capture group that will match 1 or more character that are not whitespace or literal }.
• (?=}) - A positive look-ahead that will check if we finally matched a literal }.

Here is sample code:

var re = /\${([^\s}]+)(?=})/g; 
var str = 'This is a string with ${var1} and ${var2} and {var3}';
var arr = [];
 
while ((m = re.exec(str)) !== null) {
    arr.push(m[1]);
}

alert(arr);

var str = 'This is a string with ${var1} and ${var2}';

var re = /\$\{(\w+?)\}/g;
var arr = [];
var match;
while (match = re.exec(str)) {
  arr.push(match[1]);
}

console.log(arr);