How to map array with another array of object and replace an first array elements with another arrays object value

Question

I have project in which I need to develop a specific calculator. By far everything is good but now I am stuck in one problem. I have an array of the object containing letter as key and its value as below

valueList = [{a:5}, {b:3}, {c:8}, {d:6}]

and I have an input element where user can type specific characters like this

input = "a+b-c"

how do I modifie the above string to the new string that contains values of alphabets from valueList like

newVar = "5+3-8"

I have tried below solution with no far success

const final = input.split("").map((variable) => {
  return valueList.forEach((element) => {
    if (variable === Object.keys(element)[0]) {
      return Object.values(element)[0];
    } else {
      return variable;
    }
  });
});
console.log(final);

Answer 1

First turn the valueList into an object with multiple properties, rather than an array of objects with single properties. Then use a regular expression to match any of the keys of the objects, and use a replacer function to look up the matching value on the object:

const valueList = [{a:5}, {b:3}, {c:8}, {d:6}];
const obj = Object.assign({}, ...valueList);
const input = "a+b-c";

const pattern = new RegExp(
  Object.keys(obj).join('|'),
  'g'
);
const output = input.replace(pattern, match => obj[match]);
console.log(output);