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JavaScript: else if statement

The getTypeOfSentence() function from the previous lesson only distinguishes between questions and normal sentences. Let's try to extend it to exclamation sentences:

const getTypeOfSentence = (sentence) => {
  const lastChar = sentence[sentence.length - 1];
  let sentenceType;

  if (lastChar === '!') {
    sentenceType = 'exclamation';
  } else {
    sentenceType = 'normal';
  }

  if (lastChar === '?') {
    sentenceType = 'question';
  }

  return `Sentence is ${sentenceType}`;
};

getTypeOfSentence('Who?'); // 'Sentence is question'
getTypeOfSentence('No');   // 'Sentence is normal'
getTypeOfSentence('No!');  // 'Sentence is exclamation'

We added one more test. Technically the function works, but there are semantics issues.

  • It tests for the question mark in any case, regardless of whether an exclamation point was found or not.
  • The else branch is defined for the first condition, not for the second.

It would be better to use another condition feature:

const getTypeOfSentence = (sentence) => {
  const lastChar = sentence[sentence.length - 1];
  let sentenceType;

  if (lastChar === '?') {
    sentenceType = 'question';
  } else if (lastChar === '!') {
    sentenceType = 'exclamation';
  } else {
    sentenceType = 'normal';
  }

  return `Sentence is ${sentenceType}`;
};

getTypeOfSentence('Who?'); // 'Sentence is question'
getTypeOfSentence('No');   // 'Sentence is normal'
getTypeOfSentence('No!');  // 'Sentence is exclamation'

Now all the conditions are framed in a single construction. else if means "if the previous condition is not satisfied, but this condition is". This is the scenario we get:

  • if the last character is ?, then it's a 'question'
  • else, if the last character is !, then it's an 'exclamation'
  • else it's 'normal'.

Only one of the code blocks belonging to the entire if construct will be executed.

Instructions

The digital map of Westeros that Sam has made shows Stark allies in green, enemies in red, and neutral families in gray.

Write a function, whoIsThisHouseToStarks(), which takes a family name as input and returns one of three values: 'friend', 'enemy', 'neutral'.

Rules:

  • Friends: 'Karstark', 'Tally'
  • Enemies: 'Lannister', 'Frey'
  • Any other families are considered neutral

Examples:

whoIsThisHouseToStarks('Karstark'); // 'friend'
whoIsThisHouseToStarks('Frey');     // 'enemy'
whoIsThisHouseToStarks('Joar');     // 'neutral'
whoIsThisHouseToStarks('Ivanov');   // 'neutral'
The exercise doesn't pass checking. What to do? 😶

If you've reached a deadlock it's time to ask your question in the «Discussions». How ask a question correctly:

  • Be sure to attach the test output, without it it's almost impossible to figure out what went wrong, even if you show your code. It's complicated for developers to execute code in their heads, but having a mistake before their eyes most probably will be helpful.
In my environment the code works, but not here 🤨

Tests are designed so that they test the solution in different ways and against different data. Often the solution works with one kind of input data but doesn't work with others. Check the «Tests» tab to figure this out, you can find hints at the error output.

My code is different from the teacher's one 🤔

It's fine. 🙆 One task in programming can be solved in many different ways. If your code passed all tests, it complies with the task conditions.

In some rare cases, the solution may be adjusted to the tests, but this can be seen immediately.

I've read the lessons but nothing is clear 🙄

It's hard to make educational materials that will suit everyone. We do our best but there is always something to improve. If you see a material that is not clear to you, describe the problem in “Discussions”. It will be great if you'll write unclear points in the question form. Usually, we need a few days for corrections.

By the way, you can participate in courses improvement. There is a link below to the lessons course code which you can edit right in your browser.

Definitions

  • else if - is a way to set multiple alternate conditions.


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