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SyntaxError: applying the 'delete' operator to an unqualified name is deprecated - JavaScript | MDN
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SyntaxError: applying the 'delete' operator to an unqualified name is deprecated

"applying the 'delete' operator to an unqualified name is deprecated" delete.

In this article

SyntaxError: Delete of an unqualified identifier in strict mode. (V8-based)
SyntaxError: applying the 'delete' operator to an unqualified name is deprecated (Firefox)
SyntaxError: Cannot delete unqualified property 'a' in strict mode. (Safari)

SyntaxError .

?

JavaScript delete. .

delete . "", .

, delete . , , delete.

. false.

JavaScript :

js
"use strict";

var x;

// ...

delete x;

// SyntaxError:   'delete'

, null:

js
"use strict";

var x;

// ...

x = null;

// X    ""

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