d3.permute()

d3.permute(array, indexes)

Returns a permutation of the specified array using the specified array of indexes. The returned array contains the corresponding element in array for each index in indexes, in order. For example, permute(["a", "b", "c"], [1, 2, 0]) returns ["b", "c", "a"]. It is acceptable for the array of indexes to be a different length from the array of elements, and for indexes to be duplicated or omitted.

This method can also be used to extract the values from an object into an array with a stable order. Extracting keyed values in order can be useful for generating data arrays in nested selections. For example:

var object = {yield: 27, variety: "Manchuria", year: 1931, site: "University Farm"},
    fields = ["site", "variety", "yield"];

d3.permute(object, fields); // returns ["University Farm", "Manchuria", 27]