Replace values from a string if they are present in an array of variables

Having the following array of objects:

const variables = [
                   {name: '%NAME%', value: 'joe'},
                   {name: '%EMAIL%', value: '%NAME%@mail.com'},
                   {name: '%HOBBY%', value: 'tennis'}
                  ];

And the input string:

const inputString = `Hi, my name is %NAME%', I like %HOBBY%, you can contact me at %EMAIL%`;

The function should take as arguments variables and inputString and return the following sting:

'Hi, my name is joe, I like tennis, you can contact me at joe@mail.com'

Here is the function so far:

function doMagic(variables, inputString) {
  let output = inputString;
  for (let i = 0; i < variables.length; i++) {
     output = inputString.replace(variables[i].name, variables[i].value);
  }
  return output;
}

Unfortunatelly, this only finds one occurrence, in case there are more, and it doesn’t go into nested variables, like %EMAIL%.

Any ideas to improve?

>Solution :

We can do a regex replacement with the help of a callback function:

var variables = [
                   {name: '%NAME%', value: 'joe'},
                   {name: '%EMAIL%', value: 'joe@mail.com'},
                   {name: '%HOBBY%', value: 'tennis'}
                  ];
var regex = new RegExp("(" + variables.map(x => x.name).join("|") + ")", "g");
var inputString = "Hi, my name is %NAME%, I like %HOBBY%, you can contact me at %EMAIL%";
var output = inputString.replace(regex, (m) => {
    return variables.filter(x => x.name == m)[0].value;
});
console.log(output);

The strategy here is to first build a regex alternation of names from the map. We do a global regex search for these names in the input string. For each match, the callback function replaces the name with the value from the map.