JS How to return all the people with the same last name

I'm new to coding and have been given this question, but I'm unsure to why my code doesn't work.

This is the question I have been given;

Create a function that takes an array of full names and returns an array containing only the people whose last name is Smith.

  E.g. ['Charlotte Jones', 'Rebecca Smith', 'Harry Smith', 'John Smithy', 'Smith Jones'] => ['Rebecca Smith', 'Harry Smith']

This is the code that I have written;

function getSmiths(arr) {
  return arr.filter(a =>a.includes("Smith"))
 }
 
 console.log(getSmiths(['Charlotte Jones', 'Rebecca Smith', 'Harry Smith', 'John Smithy', 'Smith Jones']));

my code is being run against this test;

describe("getSmiths", () => {
  it("returns [] when passed []", () => {
    expect(getSmiths([])).to.eql([]);
  });
 it("returns a Smith from a mixed arrau", () => {
    expect(getSmiths(["Harry Smith", "Charlotte Bank"])).to.eql([
      "Harry Smith"
    ]);
  });
  it("returns multiple Smiths from a mixed array", () => {
    expect(getSmiths(["Harry Smith", "Charlotte Bank"])).to.eql([
      "Harry Smith"
    ]);
  });
  it("ignores Smiths found in first names", () => {
     expect(getSmiths(["Smithy Jones", "Harry     Smith"])).to.eql(["Harry Smith"]);
  });
  it("ignores Smiths found in extended last names", () => {
     expect(getSmiths(["John Smith", "Chris Smithy"])).to.eql(["John     Smith"]);
  });
});

Dose anyone have any suggestion to why my code doesn't work?

Well you're using include which will search for smith in the complete string.

1. Using endsWith

let arr = ['Charlotte Jones', 'Rebecca Smith', 'Harry Smith', 'John Smithy', 'Smith Jones'];

    let op = arr.filter(e=> e.endsWith('Smith'))

    console.log(op);

2. Using regex

let arr = ['Charlotte Jones', 'Rebecca Smith', 'Harry Smith', 'John Smithy', 'Smith Jones'];

let op = arr.filter(e=> /\ssmith$/ig.test(e))

console.log(op);