I want to create an expression parser (in javascript but also examples in other languages welcomed) to grab values inside the ${ } tag.

So in the case of ${ foo bar } i want to extract "foo bar"

Thanks in advance!

CodePudding user response：

This works in typescript.

var exp = (/(?<=\${)(.*?)(?=})/g);
console.log("${foo bar} ${test 1} no test ${test 2}".match(exp));

Output

[LOG]: ["foo bar", "test 1", "test 2"]

CodePudding user response：

You can use regex to achieve this simply like this

text = '${ foo bar }';
regex = /\$\s*{\s*(.*)}/g;
matchedText = text.match(regex)[1].trim();
console.log(matchedText);

• Regex is a tool to find patterns in a string.
• The variable regex stores that pattern in this program.
• Then we try to find the substring part of the text that matches the pattern described in regex.
• text.match(regex) returns an array containing the entire matched substring and then the specific value that you're looking for in ${ foo bar } which is foo bar. Therefore we access the element on the 1 index, strip it and then store it in matchedText.