CODEWITHSUNDEEP
javascriptecmascript-6
Sean McMillan
Sean McMillan

Reputation: 10093

Which ECMAScript 6 features imply strict mode?

In ECMAScript 5 (aka JavaScript,) I can trigger strict mode by adding "use strict" at the top of my function (or file, but this is discouraged.)

I understand that in ECMAScript 6, certain syntax features will turn on strict mode, especially class, and modules (however you do those.)

In the ECMAScript 6 world, what is the complete list of ways to trigger strict mode?

Upvotes: 30

Views: 11692

Answers (1)

Bergi
Bergi

Reputation: 664589

The spec says:

  • Module code is always strict mode code.
  • All parts of a ClassDeclaration or a ClassExpression are strict mode code.
  • …

The rest are just the known things from ES5, basically every global/eval/function code that begins with the "use strict"; directive. It does work within the new ES6 function kinds (arrow, generator, method syntax) as well.

Upvotes: 32

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