javascript - "Use Strict" needed in a TypeScript file? -


i've seen posts regarding put "use strict" line in typescript code file. question is, why have @ all?

since typescript typed language, "use strict" add?

updates

  • typescript 1.8+: "use strict"; emitted in modules (read more).
  • typescript 2.1+: --alwaysstrict compiler option parses files in strict mode , emits "use strict" @ top of outputted files (read more).

you can find list of examples searching typescript's tests "in strict mode".

here's examples of code throw compile time error when "use strict";:

// future reserved keyword not allowed variable name var let,     yield,     public,     private,     protected,     static,     implements;  // "delete" cannot called on identifier var a; delete a;  // octal literals not allowed 03;

there few more examples "use strict"; throw error @ runtime. example:

"use strict"; delete object.prototype;

personally, don't find useful @ preventing me making mistakes in typescript , additional noise adds file makes me not bother writing it. said, starting in ts 2.1 i'll enable --alwaysstrict compiler option because adds slight additional strictness without code maintenance overhead.


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