fix!: Properly handle function coercer in array of coercers

[sttk]

When a type array contains 'function' or 'object', there are cases that this module returns incorrect result as follows. This pr fixes these bugs.

var normalize = require('value-or-function'), type, value;

type = ['function'];
value = function() {};
console.log(normalize(type, value));  // => undefined ... NG

type = ['object'];
value = {}
console.log(normalize(type, value));  // => {}
console.log(typeof normalize(type, value));  // => object ... OK

type = ['string', 'object'];
value = {}
console.log(normalize(type, value));  // => [object Object];
console.log(typeof normalize(type, value));  // => string ... NG

[phated]

@sttk can you rebase/update this now that I merged #13 (sorry that I forgot to review it before that other PR 😭)

[sttk]

@phated I've pushed new modifications from the current master branch.

[phated]

Thanks!

I'm currently trying to decide if the following is the correct behavior:

type = ['string', 'object'];
value = {}
console.log(normalize(type, value));  // => [object Object];
console.log(typeof normalize(type, value));  // => string ... NG

A simple object, like {}, has a toString method, which should be called to coerce it to a string. I think this was a design choice, so maybe we shouldn't change it. If you want the object coercer to be applied first, you'd want to order the array ['object', 'string'] since they are resolved in order.

Do you have an example where that situation is needed?

[phated]

@sttk I changed this PR a small amount, but I believe that I've handled most of the errors/bugs you encountered while keeping the expectation of array order.

I'm going to merge this now, but please review when you have time!