Mar 1, 2022 · Dec 24, 2021 · Dec 24, 2021 · Feb 11, 2022 · Feb 12, 2022 · Feb 12, 2022
diff --git a/packages/eslint-plugin/tests/rules/prefer-readonly-parameter-types.test.ts b/packages/eslint-plugin/tests/rules/prefer-readonly-parameter-types.test.ts
      };
      function bar(arg: MyType) {}
    `,
    // PrivateIdentifier is exempt from this rule
    {
      code: `
        class Foo {
          #privateField = 'foo';
          #privateMember() {}
        }
        function foo(arg: Foo) {}
      `,
    },
    {
      code: `
        class HasText {
          readonly #text: string;
        }

        export function onDone(task: HasText): void {}
      `,
    },
    // methods treated as readonly
    {
      code: `
        },
      ],
    },

    // parameter properties should work fine
    {
      code: `
diff --git a/packages/type-utils/src/isTypeReadonly.ts b/packages/type-utils/src/isTypeReadonly.ts
        continue;
      }

      const name = ts.getNameOfDeclaration(property.valueDeclaration);
      if (name && ts.isPrivateIdentifier(name)) {
        continue;
      }

      return Readonlyness.Mutable;
    }

diff --git a/packages/type-utils/src/propertyTypes.ts b/packages/type-utils/src/propertyTypes.ts
  escapedName?: ts.__String,
 ): ts.Type | undefined {
  // Most names are directly usable in the checker and aren't different from escaped names
  if (!escapedName || !name.startsWith('__')) {
  if (!escapedName || !isSymbol(escapedName)) {
    return checker.getTypeOfPropertyOfType(type, name);
  }

    property.getEscapedName(),
  );
 }

 // Symbolic names need to be specially handled because TS api is not sufficient for these cases.
 // Source based on:
 // https://github.com/microsoft/TypeScript/blob/0043abe982aae0d35f8df59f9715be6ada758ff7/src/compiler/utilities.ts#L3388-L3402
 function isSymbol(escapedName: string): boolean {
  return isKnownSymbol(escapedName) || isPrivateIdentifierSymbol(escapedName);
 }

 // case for escapedName: "__@foo@10", name: "__@foo@10"
 function isKnownSymbol(escapedName: string): boolean {
  return escapedName.startsWith('__@');
 }

 // case for escapedName: "__#1@#foo", name: "#foo"
 function isPrivateIdentifierSymbol(escapedName: string): boolean {
  return escapedName.startsWith('__#');
 }
diff --git a/packages/type-utils/tests/isTypeReadonly.test.ts b/packages/type-utils/tests/isTypeReadonly.test.ts
            ['type Test = Readonly<ReadonlySet<string>>;'],
            ['type Test = Readonly<ReadonlyMap<string, string>>;'],
          ])('handles fully readonly sets and maps', runTests);

          // Private Identifier.
          // Note: It can't be accessed from outside of class thus exempt from the checks.
          it.each([
            ['class Foo { readonly #readonlyPrivateField = "foo"; }'],
            ['class Foo { #privateField = "foo"; }'],
            ['class Foo { #privateMember() {}; }'],
          ])('treat private identifier as readonly', runTests);
        });

        describe('is not readonly', () => {
Original file line number	Diff line number	Diff line change
Expand Up		@@ -169,6 +169,25 @@ ruleTester.run('prefer-readonly-parameter-types', rule, {
		};
		function bar(arg: MyType) {}
		`,
		// PrivateIdentifier is exempt from this rule
		{
		code: `
		class Foo {
		#privateField = 'foo';
		#privateMember() {}
		}
		function foo(arg: Foo) {}
		`,
		},
		{
		code: `
		class HasText {
		readonly #text: string;
		}

		export function onDone(task: HasText): void {}
		`,
		},
		// methods treated as readonly
		{
		code: `
Expand DownExpand Up		@@ -222,7 +241,6 @@ ruleTester.run('prefer-readonly-parameter-types', rule, {
		},
		],
		},

		// parameter properties should work fine
		{
		code: `
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -157,6 +157,11 @@ function isTypeReadonlyObject(
		continue;
		}

		const name = ts.getNameOfDeclaration(property.valueDeclaration);
		if (name && ts.isPrivateIdentifier(name)) {
		continue;
		}

		return Readonlyness.Mutable;
		}

Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -7,7 +7,7 @@ export function getTypeOfPropertyOfName(
		escapedName?: ts.__String,
		): ts.Type \| undefined {
		// Most names are directly usable in the checker and aren't different from escaped names
		if (!escapedName \|\| !name.startsWith('__')) {
		if (!escapedName \|\| !isSymbol(escapedName)) {
		return checker.getTypeOfPropertyOfType(type, name);
		}

Expand All		@@ -34,3 +34,20 @@ export function getTypeOfPropertyOfType(
		property.getEscapedName(),
		);
		}

		// Symbolic names need to be specially handled because TS api is not sufficient for these cases.
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		// Source based on:
		// https://github.com/microsoft/TypeScript/blob/0043abe982aae0d35f8df59f9715be6ada758ff7/src/compiler/utilities.ts#L3388-L3402
		function isSymbol(escapedName: string): boolean {
		return isKnownSymbol(escapedName) \|\| isPrivateIdentifierSymbol(escapedName);
		}

		// case for escapedName: "__@foo@10", name: "__@foo@10"
		function isKnownSymbol(escapedName: string): boolean {
		return escapedName.startsWith('__@');
		}

		// case for escapedName: "__#1@#foo", name: "#foo"
		function isPrivateIdentifierSymbol(escapedName: string): boolean {
		return escapedName.startsWith('__#');
		}
Original file line number	Diff line number	Diff line change
Expand Up		@@ -82,6 +82,14 @@ describe('isTypeReadonly', () => {
		['type Test = Readonly<ReadonlySet<string>>;'],
		['type Test = Readonly<ReadonlyMap<string, string>>;'],
		])('handles fully readonly sets and maps', runTests);

		// Private Identifier.
		// Note: It can't be accessed from outside of class thus exempt from the checks.
		it.each([
		['class Foo { readonly #readonlyPrivateField = "foo"; }'],
		['class Foo { #privateField = "foo"; }'],
		['class Foo { #privateMember() {}; }'],
		])('treat private identifier as readonly', runTests);
		});

		describe('is not readonly', () => {
Expand Down