Function Name

Determine a function's name.

Usage

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

functionName( fcn )

Returns the name of a function.

var v = functionName( Math.sqrt );
// returns 'sqrt'

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

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

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

try {
    // throws...
    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' );

var v = functionName( Math.sqrt );
// returns 'sqrt'

v = functionName( Float64Array );
// returns 'Float64Array'

v = functionName( Buffer );
// returns 'Buffer'

v = functionName( Date );
// returns 'Date'

v = functionName( String );
// returns 'String'

v = functionName( Boolean );
// returns 'Boolean'

v = functionName( Function );
// returns 'Function'

v = functionName( Number );
// returns 'Number'

v = functionName( function foo() {} );
// returns 'foo'

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