Apply Chai chainable getters with an array

Question

I'm not sure how to do the following (or if it's even a smart idea), but I have something like this function:

 testProperty: function(err, data, prop, chaiMethod) { if (Array.isArray(data)) data = data[0]; var propertyValue = (isNaN(parseInt(data.value, 10))) ? data.value : parseInt(data.value, 10); return propertyValue.toString().should[chaiMethod](prop); } }; 

Where chaiMethod is an an array of strings representing the chai string I want to apply. For example:

chiMethod = ['be', 'above']

I'm trying to figure out how to apply these functions to should before I pass in the prop I'm trying to verify.

I think the answer is currying (I'm more than happy to be wrong), and if that's the case, it's a concept I've always had trouble with. Any ideas?

Answer 1

You should be able to just loop over the strings to get the value of each successive property, the final one will hopefully be the function to call:

testProperty: function(err, data, prop, chaiMethod) {

  if (Array.isArray(data)) data = data[0];

    var propertyValue = (isNaN(parseInt(data.value, 10))) ? data.value : parseInt(data.value, 10);

    var assertion = (propertyValue).should,
        fn = assertion;

    for (var i = 0, len = chaiMethod.length - 1; i < len; i++) {
        fn = fn[chaiMethod[i]];
    }
    return fn[chaiMethod[chaiMethod.length-1]](prop);    
  }

};

Also, if you want to do tests like be.above , I don't think they will work if you are converting your propertyValue to a string, so I removed that.

Note I haven't tested any of this, so you'll have to give it a go yourself.