For Medium Article: https://medium.com/@robertsavian/javascript-case-converters-using-lodash-4f2f964091cc

JavaScript Case Converter Using Lodash.js

import {camelCase, kebabCase, lowerCase, snakeCase, startCase, upperCase, upperFirst} from 'lodash';

export default class StringUtility {
  
  static toCamelCase(str) {
    return camelCase(str);
  }

  static toTitleCase(str) {
    return startCase(camelCase(str));
  }

  static toPascalCase(str) {
    return startCase(camelCase(str)).replace(/ /g, '');
  }

  static toConstantCase(str) {
    return upperCase(str).replace(/ /g, '_');
  }

  static toDotCase(str) {
    return lowerCase(str).replace(/ /g, '.');
  }

  static toKebabCase(str) {
    return kebabCase(str);
  }

  static toLowerCase(str) {
    return lowerCase(str).replace(/ /g, '');
  }

  static toPathCase(str) {
    return lowerCase(str).replace(/ /g, '/');
  }

  static toSnakeCase(str) {
    return snakeCase(str);
  }

  static toSentenceCase(str) {
    return upperFirst(lowerCase(str));
  }
  
}

JavaScript Case Converter Using Lodash.test.js

import StringUtility from './StringUtility';

describe('StringUtility', () => {
  const testStrings = ['lives-Down_by-the.River', 'Lives`Down,by~the RIVER', 'LivesDownBY  the RIVER'];

  describe('toCamelCase', () => {
    it('returns camelCase string', () => {
      const expectedResult = 'livesDownByTheRiver';

      testStrings.forEach((str) => {
        expect(StringUtility.toCamelCase(str)).toEqual(expectedResult);
      });
    });
  });

  describe('toTitleCase', () => {
    it('returns Title Case string', () => {
      const expectedResult = 'Lives Down By The River';

      testStrings.forEach((str) => {
        expect(StringUtility.toTitleCase(str)).toEqual(expectedResult);
      });
    });
  });

  describe('toPascalCase', () => {
    it('returns PascalCase string', () => {
      const expectedResult = 'LivesDownByTheRiver';

      testStrings.forEach((str) => {
        expect(StringUtility.toPascalCase(str)).toEqual(expectedResult);
      });
    });
  });

  describe('toConstantCase', () => {
    it('returns CONSTANT_CASE string', () => {
      const expectedResult = 'LIVES_DOWN_BY_THE_RIVER';

      testStrings.forEach((str) => {
        expect(StringUtility.toConstantCase(str)).toEqual(expectedResult);
      });
    });
  });

  describe('toDotCase', () => {
    it('returns dot.case string', () => {
      const expectedResult = 'lives.down.by.the.river';

      testStrings.forEach((str) => {
        expect(StringUtility.toDotCase(str)).toEqual(expectedResult);
      });
    });
  });

  describe('toKebabCase', () => {
    it('returns kebab-case string', () => {
      const expectedResult = 'lives-down-by-the-river';

      testStrings.forEach((str) => {
        expect(StringUtility.toKebabCase(str)).toEqual(expectedResult);
      });
    });
  });

  describe('toLowerCase', () => {
    it('returns lowercase string', () => {
      const expectedResult = 'livesdownbytheriver';

      testStrings.forEach((str) => {
        expect(StringUtility.toLowerCase(str)).toEqual(expectedResult);
      });
    });
  });

  describe('toPathCase', () => {
    it('returns path/case string', () => {
      const expectedResult = 'lives/down/by/the/river';

      testStrings.forEach((str) => {
        expect(StringUtility.toPathCase(str)).toEqual(expectedResult);
      });
    });
  });

  describe('toSnakeCase', () => {
    it('returns snake_case string', () => {
      const expectedResult = 'lives_down_by_the_river';

      testStrings.forEach((str) => {
        expect(StringUtility.toSnakeCase(str)).toEqual(expectedResult);
      });
    });
  });

  describe('toSentenceCase', () => {
    it('returns Sentence case string', () => {
      const expectedResult = 'Lives down by the river';

      testStrings.forEach((str) => {
        expect(StringUtility.toSentenceCase(str)).toEqual(expectedResult);
      });
    });
  });

});