obj.hasOwnProperty undefined is not a function nodejs

Hello,

I was noticing some discrepancies in some of the rendering of the nunjuck templates. After enough digging around I boiled it down to different nodejs versions between development and production. However the production machine has a more resent version of nodejs.

~ > node --version
v0.12.2

With version v0.12.x of node, this line

https://github.com/mozilla/nunjucks/blob/master/src/lib.js#L271

fails with TypeError: undefined is not a function.

Has anyone encountered this, is there any know workaround?

[devoidfury]

This could also happen if the object does not have Object in it’s prototype chain, for example:

extra = Object.create(null)

The safer way to handle this case would be to change https://github.com/mozilla/nunjucks/blob/master/src/lib.js#L271 to this:

 if(Object.prototype.hasOwnProperty.call(obj, k)) {

— the only issue with that is that it may break some older browser compatibility, so we’d need to add extra logic for that.

[asprouse]

@carljm This is enough of a problem that ESLint has a rule about it. http://eslint.org/docs/rules/no-prototype-builtins This setting was enabled in v4 of Airbnb’s widely (43k+ stars) used ESLint config. I have noticed some libraries, notably graphql-js, creating objects with Object.create(null);passing them into nunjucks throws this error.