CODEWITHSUNDEEP
javascriptnode.js
domipoke
domipoke

Reputation: 35

Number prototype

Hi everyone i need an help. I try to modify Number.prototype to add the function sum. I want to add some numbers to my initial number.

Number.prototype.sum = async (...nums) => {
    var x = //What I have to write to have my inizial number here?
    for (var i = 0;i<nums.length;i++) {
        x=x+nums[i]
    }
    return x
}
console.log((10).sum(2)) // output: 12
console.log((10).sum(4,6)) // output: 20

(I use visual studio code and the hint after this. is only number) I tried with:

Number.prototype.valueOf(this)

Number.prototype.valueOf(this.number)

Number.parseInt(this.toString())

Number.parseFloat(this.toString())

Number.parseInt(this.number.toString())

Number.parseFloat(this.number.toString())

this.valueOf()

this.number.valueOf()

Upvotes: 0

Views: 164

Answers (1)

Đinh Carabus
Đinh Carabus

Reputation: 3494

You have to use function to access the correct this context (which is the number that the method is called on). Arrow functions inherit their this context from the parent scope (the global object in this case). Also async is not needed since you are not doing anything asynchronous here:

Number.prototype.sum = function (...nums) {
    var x = this
    for (var i = 0; i < nums.length; i++) {
        x = x + nums[i]
    }
    return x
}

console.log((1).sum(2, 3))

Aside from the fact that augmenting native prototypes is a bad idea, wouldn't you think that a function like this is better suited for the Array prototype?

Upvotes: 2

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