我应该如何清理参数？

Question

参数类型检查的约定是什么？我正在为我自己和其他一些人使用的小型图书馆工作。库中有许多接受大量参数的方法。我应该检查以确保这些参数是正确的类型。如果是这样，最好的方法是什么。

我目前正在为2d向量做的示例：

function Vec2 (x, y) {
    // default to 0's if numbers aren't provided
    // should this check for numbers differently?
    // should this just fail silently?
    // should this just accept whatever's given to it?

    if (x.constructor !== Number) {
        x = 0;
    }

    if (y.constructor !== Number) {
        y = 0;
    }

    // store components
    this.x = x;
    this.y = y;
}

// an example method
Vec2.prototype.plus = function (vector) {
    // throw a type-error if its not "Vec2"
    // should this check for "Vec2"'s differently?
    // should this just fail silently?
    // should this use duck-typing and accept anything resembling {x : 1, y : 2}?
    // should this just accept whatever's given to it?
    if (vector.constructor !== Vec2) {
        throw new TypeError('The provided vector is not of type "Vec2".');
    }

    return new Vec2(this.x + vector.x, this.y + vector.y);
};