JS: why do i need brackets to call a method on number?

Question

function func2method(f){
    return function(y) {
        return f(this, y);
    };
}

Number.prototype.add = func2method(function(x, y){return x+y});

Why do I have to use brackets to call this method on a number?

For example, 3.add(4) won't work while (3).add(4) works perfectly fine.

It's because it's getting mixed up with numeric grammar. `3.` is a valid number literal. — MinusFour, Apr 02 '17 at 21:32
Yeah, as MinusFour says, your intentions are ambiguous with `3.add(4)`. — jakeehoffmann, Apr 02 '17 at 21:33

score 3 · Accepted Answer · edited Apr 02 '17 at 22:00

3

Because 3.0 is not the same as (3)['0']

Literals are interpreted differently. The point . represents a decimal point on a numeric literal, but the point . on an object represents a property accessor (translated to square bracket notation above)

edited Apr 02 '17 at 22:00

Lightness Races in Orbit

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answered Apr 02 '17 at 21:37

Isaac

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JS: why do i need brackets to call a method on number?

1 Answers1