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Severity: error
Category: access-modifiers
Stage: Stage 1

Description

SJS enforces access modifiers at compile time:

  • private members are accessible only within the class that declares them.
  • protected members are accessible within the declaring class and its subclasses.

Accessing a private member from outside the class, or a protected member from a non-subclass context, is a type error.

Example

// ✗ error
class Account {
  private balance: number = 0

  protected internalId: string = "acc-1"
}

const a = new Account()
console.log(a.balance)     // SJS-E014 — private
console.log(a.internalId)  // SJS-E014 — protected, not in a subclass

Fix

Expose state through a public accessor or method:

// ✓ correct
class Account {
  private balance: number = 0
  protected internalId: string = "acc-1"

  getBalance(): number {
    return this.balance
  }
}

const a = new Account()
console.log(a.getBalance())   // ✓ public method

For protected members, access them from a subclass:

// ✓ correct — subclass access
class SavingsAccount extends Account {
  describe(): string {
    return `ID: ${this.internalId}`   // ✓ allowed in subclass
  }
}

Related codes

  • SJS-E015 — cannot narrow an access modifier on an overriding method
Documentation