isReadOnlyPropertyIn

Test if an object's own or inherited property is read-only.

Usage

var isReadOnlyPropertyIn = require( '@stdlib/assert/is-read-only-property-in' );

isReadOnlyPropertyIn( value, property )

Returns a boolean indicating if a value has a read-only property.

var defineProperty = require( '@stdlib/utils/define-property' );

var bool;
var obj;

function Foo() {
    this.foo = 'bar';
    return this;
}

defineProperty( Foo.prototype, 'beep', {
    'configurable': false,
    'enumerable': false,
    'writable': false,
    'value': 'boop'
});

defineProperty( Foo.prototype, 'accessor', {
    'configurable': false,
    'enumerable': true,
    'get': function getter() {
        return obj.foo;
    }
});

obj = new Foo();

bool = isReadOnlyPropertyIn( obj, 'foo' );
// returns false

bool = isReadOnlyPropertyIn( obj, 'beep' );
// returns true

bool = isReadOnlyPropertyIn( obj, 'accessor' );
// returns true

Notes

  • Value arguments other than null or undefined are coerced to objects.

    var bool = isReadOnlyPropertyIn( 'beep', 'length' );
    // returns true
    
  • Property arguments are coerced to strings.

    var defineProperty = require( '@stdlib/utils/define-property' );
    
    var obj = {};
    
    defineProperty( obj, 'null', {
        'configurable': false,
        'enumerable': true,
        'writable': false,
        'value': true
    });
    
    var bool = isReadOnlyPropertyIn( obj, null );
    // returns true
    

Examples

var isReadOnlyPropertyIn = require( '@stdlib/assert/is-read-only-property-in' );

var bool = isReadOnlyPropertyIn( 'a', 'length' );
// returns true

bool = isReadOnlyPropertyIn( { 'a': 'b' }, 'a' );
// returns false

bool = isReadOnlyPropertyIn( [ 'a' ], 0 );
// returns false

bool = isReadOnlyPropertyIn( { 'null': false }, null );
// returns false

bool = isReadOnlyPropertyIn( { '[object Object]': false }, {} );
// returns false

bool = isReadOnlyPropertyIn( {}, 'toString' );
// returns false

bool = isReadOnlyPropertyIn( {}, 'hasOwnProperty' );
// returns false

bool = isReadOnlyPropertyIn( null, 'a' );
// returns false

bool = isReadOnlyPropertyIn( void 0, 'a' );
// returns false