javascript: use strict is unnecessary inside of modules

Question

tsling raise an error:

Line 1: 'use strict' is unnecessary inside of modules (strict)

this is my code

"use strict";

function Foo() {}

Foo.prototype.sayHello= function () {
    console.log("hello!");
}

if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') {
    module.exports = { 
        Foo: Foo
    };
}

how fix this error?

Side note

my code is used both module and vanilla javascript. I want use "strict mode" only for vanilla javascript.

maybe i can use

if (typeof module !== 'undefined') {
    "use strict";
}

for enabling strict mode only for vanilla javascript?

Line 1: 'use strict' is unnecessary inside of modules strict i think this line answer your question — Abslen Char, Mar 20 '18 at 13:49
Possible duplicate of [Not recommended to use "use strict" in ES6?](https://stackoverflow.com/questions/31685262/not-recommended-to-use-use-strict-in-es6) — Durga, Mar 20 '18 at 13:51

Joseph · Answer 1 · 2018-03-20T13:51:28.220

17

Remove 'use strict'. As the error mentions, it's unnecessary. Modules are expected to execute in strict mode. Compilers will add it for you when you export the module into a script for non-module consumption (i.e. UMD/CJS). See --alwaysStrict option for TS.

edited Mar 20 '18 at 13:51

answered Mar 20 '18 at 13:49

Joseph

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8

ok, but my code is used both in module and vanilla javascript – ar099968 Mar 20 '18 at 13:50

score 6 · Answer 2 · answered Apr 22 '20 at 19:21

6

ES6 modules are always in strict mode.

answered Apr 22 '20 at 19:21

Ginie

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javascript: use strict is unnecessary inside of modules

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