Javascript：处理常量和跨浏览器的兼容性

Question

Just read that ( const ) Behavior will vary across browser implementations . The answer I pointed to is pretty old (2012) so, is it still so bad?

As I need cross browser compatibility in my project so should I avoid use of const keyword?

If 'yes' - how do I replace one?

UPD:

Just checked the description on the developer.mozilla.org . And YES: looks like it is that bad...

Answer 1

const isn't available in old browsers (I'm looking at you, IE, Safari).

If you want to play safe, and you have no build step (Babel, TypeScript, etc), use only var . Both Babel and TypeScript will compile your const s and let s to var s. So if you use any of those tools, you can use const and let freely.

Be mindful that var is not strictly equivalent to either let or const . ( var is hoisted, and has a different scope).

Also, if you don't care about IE or Safari, you can pretty much use const without a build tool.

Answer 2

You can just simply use var instead of const to support old browsers. (** remember var isn't equivalent to const to some extent) and to protect a var from being changed you can just put it inside a private scope instead of global. (so it'll work partly like a const )