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id	title	challengeType
5d792534408c5be896b0a46e	Part 37	0

Description

The hasOwnProperty method checks if a key exists in an object. So spreadsheetFunctions.hasOwnProperty("") would return true, but replacing "" with anything else would make it return false.

Chain hasOwnProperty to spreadsheetFunctions to check if the fn.toLowerCase() key exists in spreadsheetFunctions.

Instructions

Tests

tests:
  - text: See description above for instructions.
    testString: assert(code.replace(/\s/g, "").includes("returnstr2.replace(regex,(match,fn,args)=>spreadsheetFunctions.hasOwnProperty(fn.toLowerCase()))"));

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, (_, arg1, fn, arg2) =>
    infixToFunction[fn](parseFloat(arg1), parseFloat(arg2))
  );

const highPrecedence = str => {
  const regex = /([0-9.]+)([*\/])([0-9.]+)/;
  const str2 = infixEval(str, regex);
  return str === str2 ? str : highPrecedence(str2);
};

const spreadsheetFunctions = {
  "": x => x
};

const applyFn = str => {
  const noHigh = highPrecedence(str);
  const infix = /([0-9.]+)([+-])([0-9.]+)/;
  const str2 = infixEval(noHigh, infix);
  const regex = /([a-z]*)\(([0-9., ]*)\)(?!.*\()/i;
  const toNumberList = args => args.split(",").map(parseFloat);
  const applyFunction = (fn, args) =>
    spreadsheetFunctions[fn.toLowerCase()](toNumberList(args));
  return str2.replace(regex, (match, fn, args) => spreadsheetFunctions);
}


</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, (_, arg1, fn, arg2) =>
    infixToFunction[fn](parseFloat(arg1), parseFloat(arg2))
  );

const highPrecedence = str => {
  const regex = /([0-9.]+)([*\/])([0-9.]+)/;
  const str2 = infixEval(str, regex);
  return str === str2 ? str : highPrecedence(str2);
};

const spreadsheetFunctions = {
  "": x => x
};

const applyFn = str => {
  const noHigh = highPrecedence(str);
  const infix = /([0-9.]+)([+-])([0-9.]+)/;
  const str2 = infixEval(noHigh, infix);
  const regex = /([a-z]*)\(([0-9., ]*)\)(?!.*\()/i;
  const toNumberList = args => args.split(",").map(parseFloat);
  const applyFunction = (fn, args) =>
    spreadsheetFunctions[fn.toLowerCase()](toNumberList(args));
  return str2.replace(
    regex,
    (match, fn, args) =>
      spreadsheetFunctions.hasOwnProperty(fn.toLowerCase())
  );
}
</script>

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