IsNull()

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Determines whether given object is null or not

IsNull( object=any );

Returns: Boolean

Argument Description
object
any, required 		edit

Object for which you perform the null check.

Usage Notes

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Always use scoped variable references with isNull().

When a null argument shares a name with an outer-scoped variable, isNull() can return the wrong result / unexpected due to scope cascading:

name = "default";

function greet( name ) {
    if ( isNull( name ) ) {
        writeOutput( "Hello stranger" );
    } else {
        writeOutput( "Hello #name#" );
    }
}

greet( javacast( "null", "" ) );
// Outputs: "Hello default" - found the outer variable, not the null argument!

Use scoped references to reliably check for null:

if ( isNull( arguments.name ) ) { ... }
if ( isNull( local.result ) ) { ... }
if ( isNull( variables.config ) ) { ... }

See recipe-null-support for more information on null handling in CFML.

Examples

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v1="test";
writeDump(isnull(v1));//false
v2;//Defining empty variable or v2=nullValue();
writeDump(isnull(v2));//true

See also