How to interpolate variables in strings in JavaScript, without concatenation?

Question

I know in PHP we can do something like this:

$hello = \"foo\";
$my_string = \"I pity the $hello\";

Output: \"I pity the foo\"<

Answer 1

I would use the back-tick ``.

let name1 = 'Geoffrey';
let msg1 = `Hello ${name1}`;
console.log(msg1); // 'Hello Geoffrey'

But if you don't know name1 when you create msg1.

For exemple if msg1 came from an API.

You can use :

let name2 = 'Geoffrey';
let msg2 = 'Hello ${name2}';
console.log(msg2); // 'Hello ${name2}'

const regexp = /\${([^{]+)}/g;
let result = msg2.replace(regexp, function(ignore, key){
    return eval(key);
});
console.log(result); // 'Hello Geoffrey'

It will replace ${name2} with his value.