There are two commonly used functions in Node for combining path segments: path.join() and path.resolve().

The difference between them is:

path.join() will concatenate and normalize all arguments in a single path.

path.join('/a', 'b', 'c') // '/a/b/c'
path.join('a', 'b', 'c') // 'a/b/c'
path.join('/a', '/b', '/', '/c') // '/a/b/c'

path.resolve() will treat segments starting with / as the root directory and ignore all previous segments. Another difference is that path.resolve() will always result in an absolute path. When none of the segments starts with /, it will use the current working directory as the base directory.

// Same as path.join
path.resolve('/a', 'b', 'c') // '/a/b/c'

// Assuming that we're running this in /Users/hendrik/code/project
path.resolve('a', 'b', 'c') // '/Users/hendrik/code/project/a/b/c'

// All previous parts starting with `/` will be ignored
path.resolve('/a', '/b', '/', '/c') // '/c'