freeCodeCamp/curriculum/challenges/italian/15-javascript-algorithms-an.../learn-functional-programmin.../step-017.md

1.8 KiB

id title challengeType dashedName
5d79253386060ed9eb04a070 Step 17 0 step-17

--description--

The match parameter is currently unused, which can lead to unused variable warnings in some linters.

To fix this, prefix or replace it with an underscore (_) - both ways signal to the reader and linter that you're aware you don't need this.

Note that a single underscore can only be used once in a function and may conflict with some libraries (Lodash, Underscore.js).

--hints--

See description above for instructions.

assert(code.replace(/\s/g, '').includes('str.replace(regex,(_'));

--seed--

--before-user-code--

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Spreadsheet</title>
  <style>
    #container {
      display: grid;
      grid-template-columns: 50px repeat(10, 200px);
      grid-template-rows: repeat(11, 30px);
    }
    .label {
      background-color: lightgray;
      text-align: center;
      vertical-align: middle;
      line-height: 30px;
    }
  </style>
</head>
<body>
<div id="container">
  <div></div>
</div>

--after-user-code--

</body>
</html>

--seed-contents--

<script>

const infixToFunction = {
  "+": (x, y) => x + y,
  "-": (x, y) => x - y,
  "*": (x, y) => x * y,
  "/": (x, y) => x / y
};

--fcc-editable-region--
const infixEval = (str, regex) =>
  str.replace(regex, (match, arg1, fn, arg2) =>
    infixToFunction[fn](parseFloat(arg1), parseFloat(arg2))
  );
--fcc-editable-region--


</script>

--solutions--

<script>
const infixToFunction = {
  "+": (x, y) => x + y,
  "-": (x, y) => x - y,
  "*": (x, y) => x * y,
  "/": (x, y) => x / y
};

const infixEval = (str, regex) =>
  str.replace(regex, (_, arg1, fn, arg2) =>
    infixToFunction[fn](parseFloat(arg1), parseFloat(arg2))
  );
</script>