How it works
Whitespace mode applies trim, trimStart, or trimEnd to the complete string or each CRLF/LF row. Custom mode builds a set from the entered UTF-16 units and removes matching units only while they occur at the selected edges.
- Both outer edges are selected first because that matches String.prototype.trim.
- Per-line and custom-character modes are opt-in because they can remove meaningful indentation or punctuation.
Worked example
Trim whitespace from lines
Remove leading and trailing spaces from each line
Input
hello world
foo bar
Output
hello world
foo bar
When to use this
Copied API tokens lose accidental outer newlines, exported columns shed surrounding spaces, and fixed marker characters are removed from pasted labels.
Edge cases
- Whole-document mode leaves spaces at the beginning of interior lines because they are not document edges.
- Per-line mode strips indentation and rejoins Windows CRLF rows with LF.
- Custom characters ab trim any run of a or b at an edge, not one literal ab substring.