函数列表上的typescript映射

来自haskell背景,我想映射一个函数列表。例如,我有:

functions fnA(x){ return true }
function  fnB(x){ return false }

// I would like to write this code that applies the same value to all functions
[ fnA, fnB ] .map ( (fn : any) => fn('hello world') )

但是我有个错误:

(x : any) => boolean' cannot be used as an index type.