How do I implement text formatting with rules?

Question

Let me start with what we already know. JS Engine finds ${... } in `` and executes the expression inside, then puts whatever that returns as a string. Okay, this is build-in functionality:

const name = "Dick Smith";

const str = `Hello, ${name}`; 

console.log(str); // Hello, Dick Smith

Now, in this case I will use "" and let's say I want to find every () and do the same thing, how can I implement that? How should that magicFunction() look like? EXP:

const name "Dick Smith";

const str = magicFunction("Hello, (name)");

console.log(str); // Hello, Dick Smith

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Details:

That magic function gets a string as a parameter and returns another string.

function magicFunction(str){
  // Does some magic
  return str;
}

Help

You can use eval() to execute the expression, if you want.

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NOTE: inside of () can be everything, even function expressions like () => {} or () => ("Hello") or even (function foo(){...})() . Anyway, it can be everything that the JS engine can understand and execute.

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Answer 1

This is basic idea covering only the scenario mentioned in the question. You need to expand it to your exact requirement by improving the regex.

 const magicFunction = (input) => { const regex = /(?:\([^\(\)]*\))/g; const matches = input.match(regex); matches.map(match => { console.log(`Match: ${match}`); console.log(`Expression: ${eval(match)}`); input = input.replace(match, eval(match)); }); document.write(input); } const name = "Dheemanth Bhat"; const skill = () => "JavaScript"; const age = 27; const rep = 1749 + 25; const str = magicFunction("name: (name), age: (age) skill: (skill) rep: (rep).");

NOTE : Explanation for the regex can be found here .