[Ramda] Basic Curry with Ramda
var _ = R; /*****************************************
C U R R Y I N G E X A M P L E
******************************************/ // We've got a nice multiply function.
// It takes two arguments. console.log( _.multiply(3, 4) ); // But it has been secretly curried already
// so we can feed it fewer arguments and it
// will return a new function.
//
// How about making a function to double a
// value? Done.
var double = _.multiply(2); console.log( double(13) ); /*****************************************
Y O U R T U R N
******************************************/ // _.split pulls a string apart around a
// given value
console.log( _.split('i', 'mississippi') ); // -- Challenge 1 ------------------------
// Make a function called "words" which
// returns a list of words in a string.
// Use only the split function and
// currying. console.log("Testing challenge 1..."); var words = _.split(' '); // change this
assertEqualArrays(
['one', 'two', 'three'],
words('one two three')
);
console.log("passed"); // -- Challenge 2 ------------------------
// Create a function to triple every
// number in a list using only
// _.multiply and _.map. console.log("Testing challenge 2..."); var tripleList = _.map(_.multiply(3));
assertEqualArrays([3,6,9], tripleList([1,2,3])); console.log("passed"); // -- Challenge 3 ------------------------
// Create a function to find the largest
// number in a list. You can use the
// greater(a,b) function which returns the
// greater of its two inputs. You can do
// this with currying and one of the list
// functions _.map, _.filter, or _.reduce. console.log("Testing challenge 3..."); var greater = function(a,b) {
return a > b ? a : b;
}; var max = _.reduce(greater, -Infinity);
assertEqual(9, max([1,-3483,9,7,2]));
assertEqual(-1, max([-21,-3483,-2,-1])); console.log("passed"); console.log("All tests pass.");
/******************************************
B A C K G R O U N D C O D E
*******************************************/ function assertEqualArrays(x,y) {
if(x.length !== y.length) throw("expected "+x+" to equal "+y);
for(var i in x) {
if(x[i] !== y[i]) {
throw("expected "+x+" to equal "+y);
}
}
}
function assertEqual(x,y){
if(x !== y) throw("expected "+x+" to equal "+y);
}
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