is-function.js

function is(val, type){

    switch(type){
        case "finite":
            return typeof val === "number" && Number.isFinite(val); 
        case "integer":
            return typeof val === "number" && Number.isInteger(val); 
        case "NaN": 
            return typeof val === "number" && Number.isNaN(val);
        case "positive":
            return typeof val === "number" && val >= 0;
        case "negative":
            return typeof val === "number" && val < 0;
        case "even":
            return typeof val === "number" && val%2 === 0;
        case "odd":     
            return typeof val === "number" && val%2 === 1;
        case "null":
            return typeof val === "object" && !val;  
        case "array":   
            return typeof val === "object" && Object.prototype.toString.call(val) === '[object Array]';
        case "object":
            return typeof val === "object" && !!val;
        default:
            return typeof val === type;
    }

}

console.log(is(undefined, "undefined"));//true
console.log(is(3, "undefined"));//false

console.log(is(true, "boolean"));//true
console.log(is(3, "boolean"));//false

console.log(is(3, "number"));//true
console.log(is(null, "number"));//false

console.log(is(3, "finite"));//I believe you see the pattern here
console.log(is(undefined, "finite"));//by now

console.log(is(3, "integer"));
console.log(is(true, "integer"));

console.log(is(NaN, "NaN"));
console.log(is(3, "NaN"));

console.log(is(3, "odd"));
console.log(is(4, "odd"));

console.log(is(4, "even"));
console.log(is(3, "even"));

console.log(is("test", "string"));
console.log(is(3, "string"));

console.log(is(null, "null"));
console.log(is({}, "null"));

console.log(is([], "array"));
console.log(is(null, "array"));

console.log(is({}, "object"));
console.log(is(null, "object"));