breaking change in 2.0 (null, undefined, arguments, ok, true, false, empty, exist)

Before the 2.0 release of Chai, these assertions could be written as properties or as functions. For example:

expect(foo).to.be.true;
expect(foo).to.be.true();

expect(foo).to.be.empty;
expect(foo).to.be.empty();

expect(foo).to.exist;
expect(foo).to.exist();

expect(foo).to.be.null;
expect(foo).to.be.null();

The documentation on chaijs.com even explained that this dual-syntax was there to play nice with some IDEs and linting tools that flag the non-function syntax as an error. But in 2.0, the function syntax no longer exists. Was it removed by accident, or was there a reason for it?

[keithamus]

For more context on all of this:

• #41 was the initial proposal to add method syntax (.to.be.true()).
• #297 was the PR that was merged by me.
• #302 is where the original discovery that the two styles were incompatible with each other was.
• #306 is where we reverted the change.
• https://github.com/chaijs/chai/releases/tag/v2.0.0 is where the release notes are, describing the reverted change
• #321 and #326 are duplicates of this issue.

[keithamus]

I think the dust has settled on this now. I’m going to close this one, as I’m pretty sure we’re sticking with the property style of assertions. dirty-chai exists and is a perfectly suitable plugin for this - and is compatible with all other plugins.