isUndefined

Test if a value is undefined.

Usage

var isUndefined = require( '@stdlib/assert/is-undefined' );

isUndefined( value )

Tests if a value is undefined.

var bool = isUndefined( undefined );
// returns true

Examples

var isUndefined = require( '@stdlib/assert/is-undefined' );

var bool;
var x;

bool = isUndefined( x );
// returns true

bool = isUndefined( undefined );
// returns true

bool = isUndefined( void 0 );
// returns true

bool = isUndefined( 'beep' );
// returns false

bool = isUndefined( 5 );
// returns false

bool = isUndefined( null );
// returns false

bool = isUndefined( true );
// returns false

bool = isUndefined( {} );
// returns false

bool = isUndefined( [] );
// returns false

bool = isUndefined( function foo() {} );
// returns false

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See Also

• @stdlib/assert/is-null: test if a value is null.
• @stdlib/assert/is-undefined-or-null: test if a value is undefined or null.