Вы можете найти весь код в этом посте в репозитории Github.

Проблемы, связанные со строками

Буквенно-цифровой

/**
 * @param {any} char
 * @return {Boolean}
 */

function isAlphaNumeric(char) {
  return /[A-Za-z0-9]/.test(char);
}

// Usage example
console.log(isAlphaNumeric("a")); // => true
console.log(isAlphaNumeric(0)); // => true
console.log(isAlphaNumeric("!")); // => false

Случай с верблюдом Случай со змеей

// camel case to snake case
/**
 * @param {string} str
 * @return {string}
 */
function toKebabCase(str) {
  let temp = str.replace(/[A-Z]/g, function (i) {
    return "_"   i.toLowerCase();
  });

  if (temp[0] === "_") {
    temp = temp.slice(1);
  }

  return temp;
}

// Usage example
console.log(toKebabCase("testMethod")); // => "test_method"

// snake case to camel case
/**
 * @param {string} str
 * @return {string}
 */
function toCamelCase(str) {
  return str.replace(
    /([a-z])_([a-z])/gi,
    (_, left, right) => left   right.toUpperCase()
  );
}

// Usage example
console.log(toCamelCase("test_method")); // => "testMethod"

Сравните номера версий

/**
 * @param {string} version1
 * @param {string} version2
 * @return {number}
 */

function compareVersion(version1, version2) {
  const v1Arr = version1.split(".");
  const v2Arr = version2.split(".");

  for (let i = 0; i  v2Num) {
      return 1;
    } else if (v1Num  1, meaning first one is greater
console.log(compareVersion("12.1.0", "12.1.2")); // => -1, meaning latter one is greater
console.log(compareVersion("5.0.1", "5.0.1")); // => 0, meaning they are equal.

Сортировка номеров версий

/**
 * @param {string[]} versions
 * @return {string[]}
 */

function sortVersions(versions) {
  return versions.sort((a, b) => {
    const aParts = a.split(".").map(Number);
    const bParts = b.split(".").map(Number);

    for (let i = 0; i  [ '0.1.1', '0.302.1', '2.3.3', '4.2', '4.3.4.5', '4.3.5' ]

/**
 * @param {string} str
 * @return {string}
 */

function compress(str) {
  if (!str) {
    return "";
  }

  let compressed = "";
  let count = 1;

  for (let i = 1; i  1) {
        compressed  = count;
      }
      count = 1;
    }
  }

  return compressed;
}

// Usage example
console.log(compress("a")); // 'a'
console.log(compress("aa")); // 'a2'
console.log(compress("aaa")); // 'a3'
console.log(compress("aaab")); // 'a3b'
console.log(compress("aaabb")); // 'a3b2'
console.log(compress("aaabba")); // 'a3b2a'

/**
 * @param {string} str
 * @return {string}
 */

function compress(str) {
  if (!str) {
    return "";
  }

  let compressed = "";
  let count = 1;

  for (let i = 1; i  1) {
        compressed  = count;
      }
      count = 1;
    }
  }

  return compressed;
}

// Usage example
console.log(compress("a")); // 'a'
console.log(compress("aa")); // 'a2'
console.log(compress("aaa")); // 'a3'
console.log(compress("aaab")); // 'a3b'
console.log(compress("aaabb")); // 'a3b2'
console.log(compress("aaabba")); // 'a3b2a'

/**
 * @param {string} str
 * @return {string}
 */

function compress(str) {
  if (!str) {
    return "";
  }

  let compressed = "";
  let count = 1;

  for (let i = 1; i  1) {
        compressed  = count;
      }
      count = 1;
    }
  }

  return compressed;
}

// Usage example
console.log(compress("a")); // 'a'
console.log(compress("aa")); // 'a2'
console.log(compress("aaa")); // 'a3'
console.log(compress("aaab")); // 'a3b'
console.log(compress("aaabb")); // 'a3b2'
console.log(compress("aaabba")); // 'a3b2a'

/**
 * @param {string} str
 * @return {string}
 */

function compress(str) {
  if (!str) {
    return "";
  }

  let compressed = "";
  let count = 1;

  for (let i = 1; i  1) {
        compressed  = count;
      }
      count = 1;
    }
  }

  return compressed;
}

// Usage example
console.log(compress("a")); // 'a'
console.log(compress("aa")); // 'a2'
console.log(compress("aaa")); // 'a3'
console.log(compress("aaab")); // 'a3b'
console.log(compress("aaabb")); // 'a3b2'
console.log(compress("aaabba")); // 'a3b2a'

/**
 * @param {string} str
 * @return {string}
 */

function compress(str) {
  if (!str) {
    return "";
  }

  let compressed = "";
  let count = 1;

  for (let i = 1; i  1) {
        compressed  = count;
      }
      count = 1;
    }
  }

  return compressed;
}

// Usage example
console.log(compress("a")); // 'a'
console.log(compress("aa")); // 'a2'
console.log(compress("aaa")); // 'a3'
console.log(compress("aaab")); // 'a3b'
console.log(compress("aaabb")); // 'a3b2'
console.log(compress("aaabba")); // 'a3b2a'

/**
 * @param {string} str
 * @return {string}
 */

function compress(str) {
  if (!str) {
    return "";
  }

  let compressed = "";
  let count = 1;

  for (let i = 1; i  1) {
        compressed  = count;
      }
      count = 1;
    }
  }

  return compressed;
}

// Usage example
console.log(compress("a")); // 'a'
console.log(compress("aa")); // 'a2'
console.log(compress("aaa")); // 'a3'
console.log(compress("aaab")); // 'a3b'
console.log(compress("aaabb")); // 'a3b2'
console.log(compress("aaabba")); // 'a3b2a'