Quality Assurance Projects - Metric-Imperial Converter Example Project accepts invalid input

Describe your problem and how to reproduce it: I am working through the Unit and Functional tests for the Metric Imperial Converter and using the example project to verify my understanding. The example project accepts invalid inputs that are supposed to be rejected according to what is being filled out in the test suite. The specific one being tested is double fraction input. From the 2_functional-test.js file:

      test('Convert 3/7.2/4kg (invalid number)', function(done) {

        //done();
      });

While it is not listed as a unit or functional test the example will also accept division by zero i.e. 3/0L

Add a Link to the page with the problem: https://metric-imperial-converter--freecodecamp.repl.co/

Tell us about your browser and operating system:

• Browser Name: Mozilla Firefox
• Browser Version: 80.0
• Operating System: Windows 10

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[SaintPeter]

I took a stab at this again. This is very much an “onion” problem - many layers and they all make you cry.

Here are the assumptions:

1. Units are at lest 1 alphabetic characters preceded by the start of the input or a non-alphabet character and ending at the end of the input
2. The numbers are anything left in the string once we remove the units with the prior characteristics
3. A number is made up of numeric digits and zero or one decimals
4. Division is always a / preceded by and succeeded by a single digit.

// Takes a string in, gives a true/false out
  this.numberChecker= function (num){
    // Check for non-digits and non-periods
    if(num.match(/[^0-9.]/gi)) {
      return false;
    }

    // Check for doubled periods
    let result = num.match(/\./gi);
    if(result && result.length > 1) {
      return false;
    }

    return true;
  }

  let re_units = /(?<=^|[^a-z])([a-z]+)$/ig
  this.getNum = function(input) {
    // get and remove units
    let noUnits = input.replace(re_units,'')

    // No number passed
    if(noUnits.length === 0) {
      return 1;
    }

    // Check for division
    // Valid division is a slash with a number
    // before and after
    let parts = noUnits.split(/(?<=\d)\/(?=\d)/ig);
    if(parts.length === 2) {
      if(!this.numberChecker(parts[0]) || !this.numberChecker(parts[1])) {
        return null;
      }
      // Division Present
      try {
        let numerator = parseFloat(parts[0]);
        let denominator = parseFloat(parts[1]);

        // Catch divide by zero
        if(denominator === 0) {
          return null;
        }
        return numerator/denominator;
      } catch(e) {
        return null;
      }
    } else {
      if(this.numberChecker(noUnits)) {
        try {
          return parseFloat(noUnits)
        } catch(e) {
          return null;
        }
      }
      return null;
    }
  };

[SaintPeter]

I discovered another issue. Invalid input like a “double fraction”: https://metric-imperial-converter--freecodecamp.repl.co/api/convert?input=1//2gal

Causes a server error:

SyntaxError: Value expected (char 3)
    at createSyntaxError (/home/runner/Metric-Imperial-Converter/node_modules/mathjs/lib/expression/parse.js:1705:17)
    at parseEnd (/home/runner/Metric-Imperial-Converter/node_modules/mathjs/lib/expression/parse.js:1669:13)
    at parseParentheses (/home/runner/Metric-Imperial-Converter/node_modules/mathjs/lib/expression/parse.js:1655:12)
    at parseNumber (/home/runner/Metric-Imperial-Converter/node_modules/mathjs/lib/expression/parse.js:1626:12)
    at parseObject (/home/runner/Metric-Imperial-Converter/node_modules/mathjs/lib/expression/parse.js:1607:12)
    at parseMatrix (/home/runner/Metric-Imperial-Converter/node_modules/mathjs/lib/expression/parse.js:1532:12)
    at parseSingleQuotesString (/home/runner/Metric-Imperial-Converter/node_modules/mathjs/lib/expression/parse.js:1433:12)
    at parseDoubleQuotesString (/home/runner/Metric-Imperial-Converter/node_modules/mathjs/lib/expression/parse.js:1382:12)
    at parseSymbol (/home/runner/Metric-Imperial-Converter/node_modules/mathjs/lib/expression/parse.js:1270:12)
    at parseCustomNodes (/home/runner/Metric-Imperial-Converter/node_modules/mathjs/lib/expression/parse.js:1239:12)