Author: John Au-Yeung

Web developer specializing in React, Vue, and front end development.

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React Answers

How to get the key prop from a React element?

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Sometimes, we want to get the key prop from a React element.

In this article, we’ll look at how to get the key prop from a React element.

How to get the key prop from a React element?

To get the key prop from a React element, we can store it in a custom attribute.

For instance, we write

const onClick = (event) => {
  console.log(event.target.getAttribute("data-key"));
};

<button data-key={1} onClick={onClick}>
  Press Me
</button>

to set the data-key attribute to 1.

Then we set the onClick prop to the onClick function.

In it, we get the data-key attribute’s value with event.target.getAttribute("data-key").

event.target is the button we clicked on.

Conclusion

To get the key prop from a React element, we can store it in a custom attribute.

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JavaScript Answers

How to get all elements in the body tag using pure JavaScript?

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Sometimes, we want to get all elements in the body tag using pure JavaScript.

In this article, we’ll look at how to get all elements in the body tag using pure JavaScript.

How to get all elements in the body tag using pure JavaScript?

To get all elements in the body tag using pure JavaScript, we use the getElementsByTagName method.

For instance, we write

const elems = document.body.getElementsByTagName("*");

to call the getElementsByTagName method on the body element with '*' to get all the elements in the body element.

Conclusion

To get all elements in the body tag using pure JavaScript, we use the getElementsByTagName method.

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React Answers

How to disable options with React Select and JavaScript?

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Sometimes, we want to disable options with React Select and JavaScript.

In this article, we’ll look at how to disable options with React Select and JavaScript.

How to disable options with React Select and JavaScript?

To disable options with React Select and JavaScript, we set the isDisabled property to true.

For instance, we write

import Select from "react-select";

const ReactSelect = () => {
  const options = [
    { label: "a", value: "a", isDisabled: true },
    { label: "b", value: "b" },
  ];

  return <Select name="mySelect" options={options} />;
};

to set the options prop to the options array.

In options, we set isDisabled to true to disable the first option.

Conclusion

To disable options with React Select and JavaScript, we set the isDisabled property to true.

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JavaScript Answers

How to prevent href=”#” link from changing the URL hash with JavaScript?

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Sometimes, we want to prevent href="#" link from changing the URL hash with JavaScript.

In this article, we’ll look at how to prevent href="#" link from changing the URL hash with JavaScript.

How to prevent href="#" link from changing the URL hash with JavaScript?

To prevent href="#" link from changing the URL hash with JavaScript, we call preventDefault.

For instance, we write

<a href="/foo/bar" class="link">Foo: Bar</a>

to add a link.

Then we write

addEventListener("click", (ev) => {
  if (ev.target.classList.contains("link")) {
    ev.preventDefault();
    //...
  }
});

to add a click listener to window with addEventListener.

In the event listener, we check if the element being clicked on has class link with classList.contains.

If it’s true, then we call preventDefault to stop the default navigation behavior.

Conclusion

To prevent href="#" link from changing the URL hash with JavaScript, we call preventDefault.

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JavaScript Answers

How to convert characters to HTML entities using plain JavaScript?

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Sometimes, we want to convert characters to HTML entities using plain JavaScript.

In this article, we’ll look at how to convert characters to HTML entities using plain JavaScript.

How to convert characters to HTML entities using plain JavaScript?

To convert characters to HTML entities using plain JavaScript, we use the string replace and charCodeAt methods.

For instance, we write

const html = text.replace(/[\u00A0-\u00FF]/g, (c) => {
  return "&#" + c.charCodeAt(0) + ";";
});

to call text.replace with a regex that matches the characters we want to replace.

We call it with a callback that returns the HTML entity equivalent of the character string c being replaced.

Conclusion

To convert characters to HTML entities using plain JavaScript, we use the string replace and charCodeAt methods.