PowerTrim.M

// Based on Ken Puls' blog post - http://www.excelguru.ca/blog/2015/10/08/clean-whitespace-in-powerquery/
// Trims in the style of the Excel TRIM function - embedded whitespace is trimmed to a single space.
// This variation accepts null values in the text parameter, in which case it returns an empty string.

(optional text as text, optional char_to_trim as text) =>
let
    char = if char_to_trim = null then " " else char_to_trim,
    text2 = if text = null then " " else text,
    split = Text.Split(text2, char),
    removeblanks = List.Select(split, each _ <> ""),
    result=Text.Combine(removeblanks, char)
in
    result