JavaScript 未定義等於

Question

試圖創建一個導致此的函數

describe('introductionWithLanguageOptional(name, language)', function() {
  it('takes in two arguments, a name and a language, and language defaults to JavaScript', function() {
    expect(introductionWithLanguageOptional("Susie")).toEqual("Hi, my name is Susie and I am learning to program in JavaScript.");
  })
})

Answer 1

function introductionWithLanguageOptional(name, language = "JavaScript") {
 return `Hi, my name is ${name} and I am learning to program in ${language}.`
}