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)