Avoid the use of alert, confirm, and prompt

Docs > Datadog Security > Code Security > Static Code Analysis (SAST) > SAST Rules > Avoid the use of alert, confirm, and prompt

Metadata

ID: javascript-best-practices/no-alert

Language: JavaScript

Severity: Notice

Category: Best Practices

Description

JavaScript’s alert, confirm, and prompt functions present obtrusive UI elements that prevent further user actions by taking control of the focus. These UI elements cannot be styled.

Non-Compliant Code Examples

alert(foo)
window.alert(foo)
window['alert'](foo)
confirm(foo)
window.confirm(foo)
window['confirm'](foo)
prompt(foo)
window.prompt(foo)
window['prompt'](foo)
function alert() {} window.alert(foo)
var alert = function() {};
window.alert(foo)
function foo(alert) { window.alert(); }
function foo() { alert(); }
function foo() { var alert = function() {}; }
alert();
this.alert(foo)
this['alert'](foo)
function foo() { var window = bar; window.alert(); }
window.alert();
globalThis['alert'](foo)
globalThis.alert();
function foo() { var globalThis = bar; globalThis.alert(); }
globalThis.alert();

// Optional chaining
window?.alert(foo);
(window?.alert)(foo);

Compliant Code Examples

a[o.k](1)
foo.alert(foo)
foo.confirm(foo)
foo.prompt(foo)
// global overrides are not recommened 
// and wont be supported by this rule
// function alert() {} alert();
// var alert = function() {}; alert();
// function foo() { var alert = bar; alert(); }
// function foo(alert) { alert(); }
// var alert = function() {}; function test() { alert(); }
// function foo() { var alert = function() {}; function test() { alert(); } }
// function confirm() {} confirm();
// function prompt() {} prompt();
window[alert]();
// function foo() { this.alert(); }
// function foo() { var window = bar; window.alert(); }
// globalThis.alert();
// globalThis['alert']();
// globalThis.alert();
// var globalThis = foo; globalThis.alert();
// function foo() { var globalThis = foo; globalThis.alert(); }