d3.bisectLeft(array, x[, lo[, hi]]) Returns the insertion point for x in array to maintain

d3.sum(array[, accessor]) Returns the sum of the given array of numbers. If the array is empty, returns 0. An

bisector.left(array, x[, lo[, hi]]) Equivalent to

d3.merge(arrays) Merges the specified arrays into a single array. This method is similar to the built-in array concat