Using ternary operator requires two calls to the function.
var colour = (tryAdventurousColour() != null) ? tryAdventurousColour() : 'black';
Possible to do it in 1 line?
EDIT: Fixed syntax EDIT: Like this but better
var colour = ( (colour = tryAdventurousColour() ) != null ) ? colour : 'black';
Use JavaScript's logical or operator:
var colour = tryAdventurousColour() || 'black';
Your function tryAdventurousColour() will be executed once. If it returns a "truthy" value then that colour variable will be assigned to that value, otherwise colour will be 'black'. This fits your scenario perfectly since null is a "falsy" value.
In more general terms, the expression a || b returns a if it can be converted to true (is "truthy"), otherwise it returns b. Note that non-zero numbers, non-empty strings and objects will all be converted to true. null, undefined, 0, "" will all be converted to false. (I'm sure somebody will correct me if I've left something out.)
tryAdventurousColour() shouldn't return 0 as a valid color.
var colour = (tryAdventurousColour() != failValue) || 'black' because that will return either true or 'black'. The != expression evaluates to true or false, not to a colour. @katspaugh - good point, but then 0 would be black anyway wouldn't it? Another option is to move the default processing into the function... var colour = (tryAdventurousColour()) ? tryAdventurousColour() : 'black';
