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javascript use strict

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Vishal answered on May 5, 2020 Popularity 10/10 Helpfulness 4/10

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// Whole-Script Strict Mode Syntax
'use strict';
var v = "Hi! I'm a strict mode script!";

Popularity 10/10 Helpfulness 4/10 Language javascript

Source: developer.mozilla.org

Tags: javascript use-strict

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Contributed on May 05 2020

Vishal

0 Answers Avg Quality 2/10

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use strict

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The statement "use strict";  instructs the browser to use the Strict mode, which is a reduced and safer feature set of JavaScript.

List of features (non-exhaustive)
-Disallows global variables. (Catches missing var declarations and typos in variable names)

-Silent failing assignments will throw error in strict mode (assigning NaN = 5;)

-Attempts to delete undeletable properties will throw (delete Object.prototype)

-Requires all property names in an object literal to be unique (var x = {x1: "1", x1: "2"})

-Function parameter names must be unique (function sum (x, x) {...})

-Forbids octal syntax (var x = 023; some devs assume wrongly that a preceding zero does nothing to change the number.)

-Forbids the with keyword

-eval in strict mode does not introduce new variables

-Forbids deleting plain names (delete x;)

-Forbids binding or assignment of the names eval and arguments in any form

-Strict mode does not alias properties of the arguments object with the formal parameters. (e.g. in function sum (a,b) { return arguments[0] + b;} This works because arguments[0] is bound to a and so on. ) (See examples section below to understand the difference)

-arguments.callee is not supported

Popularity 10/10 Helpfulness 4/10 Language javascript

Source: Grepper

Tags: javascript j

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Contributed on Jul 26 2022

Motionless Mamba

0 Answers Avg Quality 2/10

JavaScript Use Strict

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"use strict";
myFunction();

function myFunction() {
  y = 3.14;   // This will also cause an error because y is not declared
}

Popularity 10/10 Helpfulness 3/10 Language javascript

Source: Grepper

Tags: javascript j

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Contributed on May 23 2022

naly moslih

0 Answers Avg Quality 2/10

JavaScript "use strict"

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'use strict';

// Error
myVariable = 9;

Popularity 10/10 Helpfulness 3/10 Language javascript

Source: Grepper

Tags: javascript j

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Contributed on May 22 2022

SAMER SAEID

0 Answers Avg Quality 2/10

'use strict'

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'use strict';

let undefined = 5; // TypeError (non-writable global)
let obj = {};
Object.defineProperty(obj1, 'x', { value: 1, writable: false });
obj.x = 2; // TypeError (non-writable property);

delete Object.prototype; // TypeError (undeletable property)
delete something; // SyntaxError (plain name)

const sum (a, b, b) { // SyntaxError (duplicated argument name)
  return a + b + b;
}

const x = 012; // SyntaxError (0-prefixed octal literal)

false.true = 10; // TypeError (property on primitive)

Popularity 6/10 Helpfulness 3/10 Language javascript

Source: www.30secondsofcode.org

Tags: javascript

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Contributed on Jan 09 2024

Himanshu Jangid

0 Answers Avg Quality 2/10

use strict javascript

Comment

// File: myscript.js

'use strict';
var a = 2;
....

Popularity 10/10 Helpfulness 2/10 Language javascript

Source: stackoverflow.com

Tags: javascript j

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Contributed on Jun 17 2020

Repulsive Raven

0 Answers Avg Quality 2/10

use strict javascript

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function doSomething() {
    'use strict';
    ...
}

Popularity 10/10 Helpfulness 2/10 Language javascript

Source: stackoverflow.com

Tags: javascript j

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Contributed on Jun 17 2020

Repulsive Raven

0 Answers Avg Quality 2/10

javascript 'use strict'

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class Person {
  constructor() {
    a = 0;
    this.name = a;
  }
}

let p = new Person(); // ReferenceError: Can't find variable: a

Popularity 10/10 Helpfulness 1/10 Language javascript

Source: Grepper

Tags: javascript j

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Contributed on May 21 2022

SAMER SAEID

0 Answers Avg Quality 2/10

JavaScript "use strict"

Comment

myVariable = 9;

Popularity 10/10 Helpfulness 1/10 Language javascript

Source: Grepper

Tags: javascript j

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Contributed on May 22 2022

SAMER SAEID

0 Answers Avg Quality 2/10

'use strict'

Comment

'use strict';
const x = "Hello from a strict mode script";

Popularity 6/10 Helpfulness 1/10 Language javascript

Source: www.30secondsofcode.org

Tags: javascript

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Contributed on Jan 09 2024

Himanshu Jangid

0 Answers Avg Quality 2/10

javascript use strict

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