Evaluates a series of condition/value pairs and returns the value for the first truthy condition.
Arguments must be provided in pairs: condition1, value1, condition2, value2, .... Use true as the final condition to provide a default.
Returns null if no conditions are met.
Examples
ifs(score > 90, 'A', score > 80, 'B', true, 'C')
→ 'A' (when score is 95)
→ 'B' (when score is 85)
→ 'C' (when score is 70)
ifs(x > 10, 'big', x > 5, 'medium')
→ null (when x is 1)