Javascript regex replace inserts extra slashes -

i'm trying clean file using javascript. file contains lines of text this:

a <- b + c / d; 

i want replace <- = when there string of non-whitespace on either side of <-, separated single space. pretty easy in theory:

line = "a <- b + c / d" result = line.replace( /(\s+) <- (\s+)/, /$1 = $2/ ) 

the above code produces /a = b/ + c / d when run. however, conceptually, should produce a = b + c / d. how can use $1-style backreferences without allowing javascript opportunity insert slashes willy-nilly?

use string second parameter:

result = line.replace( /(\s+) <- (\s+)/, "$1 = $2" );.

what happening second parameter being coerced regexp string adds slashes in replacement.