Function Name

Determine a function's name.

Usage

var functionName = require( '@stdlib/utils/function-name' );

functionName( fcn )

Returns the name of a function.

var name = functionName( Math.sqrt )
// returns 'sqrt'

If provided an anonymous function, the function returns an empty string or the string "anonymous".

var name = functionName( function(){} );
// returns '' || 'anonymous'

If provided a value which is not a function, the function throws a TypeError.

try {
	// throws...
	var name = functionName( 'beep' );
} catch ( err ) {
	console.error( err );
}

Notes

• For more information regarding the naming of anonymous functions, see
  • Function Names in ES6
  • Webkit bug 7726
  • MDN

Examples

var functionName = require( '@stdlib/utils/function-name' );

console.log( functionName( Math.sqrt ) );
// returns 'sqrt'

console.log( functionName( Float64Array ) );
// returns 'Float64Array'

console.log( functionName( Buffer ) );
// returns 'Buffer'

console.log( functionName( Date ) );
// returns 'Date'

console.log( functionName( String ) );
// returns 'String'

console.log( functionName( Boolean ) );
// returns 'Boolean'

console.log( functionName( Function ) );
// returns 'Function'

console.log( functionName( Number ) );
// returns 'Number'

console.log( functionName( function foo(){} ) );
// returns 'foo'

console.log( functionName( function(){} ) );
// returns '' || 'anonymous'