Thinkful exercises: JS functions using strings

shouter.js

function shouter(whatToShout) {
  return whatToShout.toUpperCase () + '!!!'
}

function testShouter() {
  var whatToShout = 'as you can hear i am whispering';
  var expected = 'AS YOU CAN HEAR I AM WHISPERING!!!';
  if (shouter(whatToShout) === expected) {
    console.log('SUCCESS: `shouter` is working');
  }
  else {
    console.log('FAILURE: `shouter` is not working');
  }
}

testShouter();

textNormalizer.js

function textNormalizer(text) {
  var text = "let's GO SURFING NOW everyone is learning how"
  return text.toLowerCase()
}

function testTextNormalizer() {
  var text = "   let's GO SURFING NOW everyone is learning how   ";
  var expected = "let's go surfing now everyone is learning how";
  if (textNormalizer(text) === expected) {
    console.log('SUCCESS: `textNormalizer` is working');
  }
  else {
    console.log('FAILURE: `textNormalizer` is not working');
  }
}

testTextNormalizer();

wisePerson.js

function wisePerson(wiseType, whatToSay) {
  return 'A wise ' + wiseType + ' once said: "' + whatToSay + '".';
}

function testWisePerson() {
  var wiseType = 'goat';
  var whatToSay = 'Hello World';
  var expected = 'A wise ' + wiseType + ' once said: "' +
      whatToSay + '".';
  var actual = wisePerson(wiseType, whatToSay);
  if (expected === actual) {
    console.log('SUCCESS: `wisePerson` is working');
  }
  else {
    console.log('FAILURE: `wisePerson` is not working');
  } 
}

testWisePerson();

I don't understand why on the last one the solution had the ".trim()" method, but Im guessing all it does is take the spaces between the " ".