Facing this issue while building with 'make'
touch ./node_modules/.installed--used_by_Makefile
./node_modules/.bin/lessc ./src/css/main.less > build/mathquill.css
undefinedError: Cannot read property 'eval' of null
Makefile:135: recipe for target 'build/mathquill.css' failed
make: *** [build/mathquill.css] Error 1