Your task is to write a function typeSafe that takes in a function, an array of expected argument types, and an expected return type. typeSafe will return a function that checks whether all passed arguments, as well as the return value of the wrapped function are correct.
Examples:
function add( a, b ) {
return a + b;
}
const wrappedAdd = typeSafe( add, [ "number", "number" ], "number );
wrappedAdd( 2, 2 ); // 4
wrappedAdd( 101, 12 ); // 113
wrappedAdd( "a", 2 ); // TypeError - Invalid Type!
wrappedAdd( 1 ); // TypeError - Incorrect number of arguments!
wrappedAdd( 1, 2, 3 ); // TypeError - Incorrect number of arguments!
function orderFood( food, amount ) {
return `I would like ${ amount } of the ${ food } please.`
}
const wrappedOrderFood = typeSafe( orderFood, [ "string", "number" ], "string );
wrappedOrderFood( 3, "lasagna" ); // I would like 3 of the lasagna please.
wrappedOrderFood( 0, "salad" ); // I would like 0 of the salad please.
wrappedOrderFood( 2, [ "lasagna", "pizza" ] ); // TypeError - Invalid Type!
Your function is expected to handle the following types of values:
- number
- string
- boolean
- object
- array
- null
- undefined
If any of the arguments or the return value does not match the expected type typeSafe should throw a new TypeError. You are not expected to check nested values ( i.e you don't need to see if an array is full of strings, or an object has certain properties of certain types).
The test suite can be run with npm test. Be sure to commit as soon as all tests are passing to save a timestamp. Good luck!