freeCodeCamp/part-013.md at a86b220eb767abd82bfa8db0fb028819b9a76921

Randell Dawson b9c9a95223 chore(learn): Renamed all project-based curriculum project step filenames to use 3-digit format of part-ddd.md (#39463 )

* fix: renamed basic html cat photo app steps

* fix: renamed css-variables project steps

* fix: renamed d3-dashboard filenames

* fix: renamed rpg-game filenames

* fix: renamed functional-progamming-spreadsheet filenames

* fix: renamed calorie-counter project filenames

2020-09-16 11:54:12 +05:30

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id, title, challengeType, isHidden

id	title	challengeType	isHidden
5d792533ed00e75d129e1b18	Part 13	0	true

Description

replace is a higher order function because it can take a function as argument (higher order functions can also return functions).

Pass the + function from infixToFunction to the replace method as the second argument.

This is how you would pass the - function:

str.replace(regex, infixToFunction["-"])

Instructions

Tests

tests:
  - text: See description above for instructions.
    testString: assert(infixEval("ab", /(a)b/) === "aba");

Challenge Seed

<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, "");


</script>

Before Test

<!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 Test

</body>
</html>

Solution

<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, infixToFunction["+"]);
</script>

1.8 KiB Raw Blame History