Sometimes, we may run into the ‘SyntaxError: applying the "delete" operator to an unqualified name is deprecated’ when we’re developing JavaScript apps.
In this article, we’ll look at how to fix the ‘SyntaxError: applying the "delete" operator to an unqualified name is deprecated’ when we’re developing JavaScript apps.
Fix the ‘SyntaxError: applying the "delete" operator to an unqualified name is deprecated’ When Developing JavaScript Apps
To fix the ‘SyntaxError: applying the "delete" operator to an unqualified name is deprecated’ when we’re developing JavaScript apps, we should make sure that we’re using the delete operator on object properties rather than variables.
The error message for this error is SyntaxError: Calling delete on expression not allowed in strict mode on Edge.
The error message for this error is SyntaxError: applying the 'delete' operator to an unqualified name is deprecated on Firefox.
And in Chrome, the error message for this error is SyntaxError: Delete of an unqualified identifier in strict mode.
This error is only thrown in strict mode.
For instance, the error will be thrown if we write:
'use strict';
let x;
// ...
delete x;
Instead, we should set variable values to null or undefined to make the JavaScript engine garbage collect the variable.
So we can write:
'use strict';
let x;
// ...
x = undefined;
or:
'use strict';
let x;
// ...
x = null;
Conclusion
To fix the ‘SyntaxError: applying the "delete" operator to an unqualified name is deprecated’ when we’re developing JavaScript apps, we should make sure that we’re using the delete operator on object properties rather than variables.
The error message for this error is SyntaxError: Calling delete on expression not allowed in strict mode on Edge.
The error message for this error is SyntaxError: applying the 'delete' operator to an unqualified name is deprecated on Firefox.
And in Chrome, the error message for this error is SyntaxError: Delete of an unqualified identifier in strict mode.
This error is only thrown in strict mode.
