Provide source code context when reporting errors.
npm install error-reporter``
Error on line 9, column 30: Invalid strength or weight
8 : #box1[width] == #box2[width] !strong;
9 : #box3[width] == #box4[width] !stron;
^ : -----------------------------^
10 : #box5[width] == #box6[width] !strong;
``