JavaScript test

    
        
function highlight(strings, ...values) {
  return strings.reduce((result, str, i) => {
    const value = values[i] ? `<span>${values[i]}</span>` : '';
    return result + str + value;
  }, '');
}

const language = 'JavaScript';
const years = 10;

const result = highlight`I have been coding in ${language} for ${years} years`;
console.log(result);
{}
    

    
        function analyze(...items) {
  const [first, ...rest] = items;
  const { length } = [...rest, 'bonus'];
  const result = {
    ...first,
    count: length,
  };
  
  console.log(result);
}

analyze({ id: 42, name: 'Item' }, 'a', 'b');{}
    

    
        function processData(data) {
  try {
    if (!data) {
      throw new TypeError('Data is required');
    }
    
    if (data.status === 'error') {
      throw new Error('Invalid status');
    }
    
    return data.value.toUpperCase();
  } catch (err) {
    if (err instanceof TypeError) {
      return 'Type Error';
    }
    return err.message;
  }
}

console.log(processData({ status: 'error', value: 'test' }));{}
    

    
        
function processConfig(config) {
  const settings = {
    timeout: config.timeout ?? 1000,
    retries: config.retries ?? 3,
    logging: config.logging ?? false,
    debug: config.debug || true
  };
  
  return settings;
}

const userConfig = {
  timeout: 0,
  retries: null,
  logging: false,
  debug: false
};

console.log(processConfig(userConfig));
{}
    

    
        
function task1() {
  console.log('A');
  setTimeout(() => console.log('B'), 0);
  Promise.resolve().then(() => console.log('C'));
  Promise.resolve().then(() => setTimeout(() => console.log('D'), 0));
  Promise.resolve().then(() => console.log('E'));
  setTimeout(() => console.log('F'), 0);
  console.log('G');
}

task1();
{}
    

    
        
const person = {
  name: 'Alice',
  greet() {
    return `Hello, I'm ${this.name}`;
  },
  farewell: () => `Goodbye from ${this.name}`
};

const greetFn = person.greet;
const farewellFn = person.farewell;

console.log(person.greet());
console.log(greetFn());
console.log(farewellFn());
{}
    

    
        
const user = {
  profile: {
    name: 'Alice',
    social: null,
    getDetails() {
      return { verified: true };
    }
  }
};

const result = [
  user?.profile?.name,
  user?.profile?.social?.handle,
  user.profile.getDetails?.()?.verified,
  user?.nonExistent?.property
];

console.log(result);
{}
    

    
        
function processConfig(config) {
  const settings = {
    timeout: config.timeout ?? 1000,
    retries: config.retries ?? 3,
    logging: config.logging ?? false,
    debug: config.debug || true
  };
  
  return settings;
}

const userConfig = {
  timeout: 0,
  retries: null,
  logging: false,
  debug: false
};

console.log(processConfig(userConfig));
{}
    

    
        
const partial = (fn, ...presetArgs) => {
  return function partiallyApplied(...laterArgs) {
    return fn(...presetArgs, ...laterArgs);
  };
};

const calculateTax = (taxRate, discount, price) => {
  const discounted = price - (price * discount) / 100;
  return parseFloat((discounted + (discounted * taxRate) / 100).toFixed(2));
};

const withVAT = partial(calculateTax, 20);
const withVATandDiscount = partial(withVAT, 15);

console.log(withVAT(0, 100));
console.log(withVATandDiscount(200));
console.log(partial(calculateTax, 10, 5)(50));
{}
    

    
        
const createMathOps = (base) => {
  return {
    add: (x) => base + x,
    multiply: (x) => base * x
  };
};

const createAdvancedMathOps = (base) => {
  const basicOps = createMathOps(base);
  return {
    ...basicOps,
    square: () => basicOps.multiply(base),
    addThenSquare: (x) => {
      const added = basicOps.add(x);
      return added * added;
    }
  };
};

const calculator = createAdvancedMathOps(5);
console.log(calculator.addThenSquare(3));
{}