How to filter through an array of objects and list all objects containing a certain keyword in one of it's values

Question

I am working on an array of book objects and the task is to console.log a list of all books containin "companies" or "people" in their title.

const books = [{
    title: 'How to win friends and influence people',
    authors: ['Dale Carnegie'],
    publisher: 'Pocket Books',
    year: '1936'
  }, {
    title: 'Management: tasks, responsibilities, practices',
    authors: ['Peter F. Drucker'],
    publisher: 'Harper Business',
    year: '1985'
  }, {
    title: 'Strength finder 2.0',
    authors: ['Tom Rath'],
    publisher: 'Gallup Press',
    year: '2007'
  }, {
    title: 'In search of excellence: Lessons from America\'s best-run companies',
    authors: ['Thomas Peters', ' Robert H. Waterman'],
    publisher: 'Harper Collins',
    year: '1982'
  }, {
    title: 'Built to last: Successful habits of visionary companies',
    authors: ['James C. Collins', 'Jerry I. Porras'],
    publisher: 'Harper Collins',
    year: '1994'
  }, {
    title: 'Reengineering the corporation: A manifesto for business revolution',
    authors: ['Michael Hammer', 'James A. Champy'],
    publisher: 'Harper Collins',
    year: '1993'
  }, {
    title: 'Competitive advantage: Creating and sustaining superior performance',
    authors: ['Michael E. Porter'],
    publisher: 'Free Press',
    year: '1998'
  }, {
    title: 'Crossing the chasm: Marketing and selling technology products to mainstream customers',
    authors: ['Geoffrey A. Moore', 'Regis McKenna'],
    publisher: 'Pocket Books',
    year: '1936'
  }, {
    title: '7 habits of highly effective people: Powerful lessons in personal change',
    authors: ['Stephen R. Covey'],
    publisher: 'Simon and Shuster',
    year: '1990'
  }, {
    title: 'The Six Sigma Way',
    authors: ['Peter S. Pande et al', 'Robert P. Neuman', 'Roland R. Cavanagh'],
    publisher: 'McGraw Hill',
    year: '2000'
  }, {
    title: 'The innovator\'s dilemma: When new technologies cause great firms to fail',
    authors: ['Clayton M. Christensen'],
    publisher: 'Harvard Business School Press',
    year: '1997'
  }, {
    title: 'The Essential Drucker',
    authors: ['Peter F. Drucker'],
    publisher: 'Harper Business',
    year: '2001'
  }];

So far I've tried using filter() and includes() as per below, but it's only returning books that contain the keyword "people"

let keyWord = books.filter (bookTitle => bookTitle.title.includes('people'||'companies'));
console.log(keyWord);

Answer 1

Can't use OR operator inside include(). So you can write the logic outside.

books.filter(book => book.title.includes('companies') || book.title.includes('people'))

If match needs to be case insensitive:

books.filter(book => {
    const titleLower = book.title.toLowerCase()
    return titleLower.includes('companies') || titleLower.includes('people')
  })