CODEWITHSUNDEEP
javascripttypescript
Evgenii Kosiakov
Evgenii Kosiakov

Reputation: 605

Typescript Uncaught TypeError while extending SVGTextElement

I am trying to create a simple extension for SVGTextElement, here it is:

interface SVGTextElement {
    setX(value: string): SVGTextElement;
    setY(value: string): SVGTextElement;
}

SVGTextElement.prototype.setX = (value: string): SVGTextElement => {
    var el: SVGTextElement = this;
    el.setAttribute("x", value);
    return el;
}

SVGTextElement.prototype.setY = (value: string): SVGTextElement => {
    var el: SVGTextElement = this;
    el.setAttribute("y", value);
    return el;
}

I am using this extension like this: 

const e = document.createElementNS("http://www.w3.org/2000/svg", "text");
e.setX("0");

But I am getting error:

SvgTextElementExtensions.ts:18 Uncaught TypeError: el.setAttribute is not a function

What am I doing wrong?

Upvotes: 2

Views: 148

Answers (1)

Alex
Alex

Reputation: 14503

You should not use the fat arrow syntax here, that will bind this to window, and window does not have setAttribute. Do this: 

SVGTextElement.prototype.setX = function (value: string): SVGTextElement {
    var el: SVGTextElement = this;
    el.setAttribute("x", value);
    return el;
}

SVGTextElement.prototype.setY = function (value: string): SVGTextElement {
    var el: SVGTextElement = this;
    el.setAttribute("y", value);
    return el;
}

Upvotes: 1

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