StylusError Reporting
Stylus has fantastic error reporting built-in for syntax, parse, and evaluation errors—complete with stack traces, line numbers, and filenames.
Parse Error
Parse error example:
body form input == padding 5px body form input == padding 5px Yielding:
ParseError: test.styl:3:16 1| body 2| form input 3| == padding 5px ---------------------^ 4| illegal unary "==", missing left-hand operand ParseError: test.styl:3:16 1| body 2| form input 3| == padding 5px ---------------------^ 4| illegal unary "==", missing left-hand operand Evaluation Error
This "runtime" or evaluation error is caused by passing a string to border-radius(), instead of the expected Unit (by using our helper ensure(n, 'unit')).
ensure(val, type) unless val is a type error('expected a ' + type + ', but got ' + typeof(val)) border-radius(n) ensure(n, 'unit') -webkit-border-radius n -moz-border-radius n border-radius n body border-radius '5px' ensure(val, type) unless val is a type error('expected a ' + type + ', but got ' + typeof(val)) border-radius(n) ensure(n, 'unit') -webkit-border-radius n -moz-border-radius n border-radius n body border-radius '5px' Yielding:
Error: test.styl:3:62 1| ensure(val, type) 2| unless val is a type 3| error('expected a ' + type + ', but got ' + typeof(val)) -------------------------------------------------------------------^ 4| 5| border-radius(n) 6| ensure(n, 'unit') expected a unit, but got string at ensure() (test.styl:2:17) at border-radius() (test.styl:6:16) at "body" (test.styl:10:18) Error: test.styl:3:62 1| ensure(val, type) 2| unless val is a type 3| error('expected a ' + type + ', but got ' + typeof(val)) -------------------------------------------------------------------^ 4| 5| border-radius(n) 6| ensure(n, 'unit') expected a unit, but got string at ensure() (test.styl:2:17) at border-radius() (test.styl:6:16) at "body" (test.styl:10:18)