Any way to force strict mode in node?
node.jsnode.js Problem Overview
Could not find this answer anywhere, but I did find several mailing lists where this was discussed, these are rather old however and I have no idea if this is implemented or not.
Is there anyway to force using strict mode in node.js?
Writing "use strict"; in all my .js files... well, i prefer it being forced to using strict mode, rather than adding extra boilerplate.
node.js Solutions
Solution 1 - node.js
According to Lloyd you can now place
"use strict";
at the top of your file in node >= 0.10.7, but if you want your whole app to run in strict (including external modules) you can do this
> node --use_strict
Solution 2 - node.js
In node 0.10.7 you can enforce strict mode at file level by placing "use strict"; at the top of your file. Finally!
Solution 3 - node.js
You can also use
https://npmjs.org/package/use-strict
that is, write once
require('use-strict')
or even take a step forward and use
https://npmjs.org/package/node-strict
Please note that use-strict will turn on strict more on every module required after invocation.
If you prefer a not invasive approach, I wrote another module
https://www.npmjs.org/package/strict-mode
which enables strict mode only in your package. I think that is more a "Do What I Mean" solution.
Solution 4 - node.js
Just use "use strict"; at the top of applicable files. I know it's tempting to try to cut out boilerplate, but it simply can not be done in Javascript. The node flag which shall not be named[1]
- is undocumented, and unsupported by Node itself.
- has faced proposals to remove it.
- is node-specific and is not supported in any other JavaScript engine.
- is unstandardized.
- it is not the same as
"use strict";because it is a compiler global, and like all globals you're potentially adversely impacting someone else's code. - everything is subject to bugs. strict mode and sloppy-mode may be subject to different bugs. that is to say, some strict mode bugs are unique to strict mode
Some other programmers may think this is similar to -wALL or the like, it's not. This is standardized functionality that you're enabling in an ad-hoc fashion (breaking the standard) and changing everyone's compiler semantics.
Footnotes
- The node flag is
--use_strict. Don't use it.
Solution 5 - node.js
You can also provide the strict flag on the shebang interpreter directive.
#!/usr/bin/env node --use_strict
But currently (at least pre v0.9.x) it suffers the same problems described by the comments in @chad-scira's answer discuss.
Solution 6 - node.js
It's worth noting that ESLint enforces strict mode by default. It won't stop you from running node on a file that doesn't adhere to strict mode of course, but if you have ESLint as a required part of your build and CI process, then developers will only be able to commit strict-mode code.