ramda.js

From the documentation : var duplicate = n => [n, n]; R.chain(duplicate, [1, 2, 3]); //=> [1, 1, 2, 2, 3, 3] R.chain(R.append, R.head)([1, 2, 3]); //=> [1, 2, 3, 1] The first example is very straight forward, it applies duplicate() to every element in the array and concatenates the result. But I am having trouble understanding the second example. How exactly is it mapping R.append + R.head over the array? Can someone please provide a step by step explanation for the second example ? I am familiar with compose and currying. Thanks The second example is showing how R.chain can be used things

I'm trying to accomplish this in a functional manner (with Ramda). My JSON is structured like this [ {username: 'bob', age: 30, tags: ['work', 'boring']}, {username: 'jim', age: 25, tags: ['home', 'fun']}, {username: 'jane', age: 30, tags: ['vacation', 'fun']} ] and I am trying to filter based on a value in the 'tags' property, but have not been successful. I am able to filter on ints/strings (age and username), but I can't figure out how to do so with values in nested arrays (tags). Any help would be much appreciated. There are many ways you could do this. But I think the cleanest one would

Looking at the source for Ramda.js, specifically at the "lift" function. lift liftN Here's the given example: var madd3 = R.lift(R.curry((a, b, c) => a + b + c)); madd3([1,2,3], [1,2,3], [1]); //=> [3, 4, 5, 4, 5, 6, 5, 6, 7] So the first number of the result is easy, a , b , and c , are all the first elements of each array. The second one isn't as easy for me to understand. Are the arguments the second value of each array (2, 2, undefined) or is it the second value of the first array and the first values of the second and third array? Even disregarding the order of what's happening here, I