code: function partial1 (f, x) {
      return function partiallyApplied1 () {
        // Using slice or splice on `arguments` causes the function to be
        // unoptimizable. Who doesn't like optimization?
        var args = map(identity, arguments);
  
        args.unshift(x);
        return f.apply(null, args);
      };
    }
docs: Partially applies 1 argument to a function.