Highlight assignment of variable in class construction

BankAccount.assignment.ts

class BankAccount {
  private balance;

  constructor(funds) {
    this.balance = funds;
  }

  public withdraw(amount) {
    this.balance = this.balance - amount; // <-- assign `this.balance` a new value
  }

  public checkBalance() {
    return this.balance;
  }
}

const bankAccount = new BankAccount(100);
bankAccount.withdraw(20);
bankAccount.checkBalance(); // 80