Category: JavaScript

Categories
Vue Answers

How to add condition in v-bind:style with Vue.js?

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Sometimes, we want to add condition in v-bind:style with Vue.js.

In this article, we’ll look at how to add condition in v-bind:style with Vue.js.

How to add condition in v-bind:style with Vue.js?

To add condition in v-bind:style with Vue.js, we can set the style prop to the style string we want.

For instance, we write

<template>
  <input
    type="text"
    v-bind:style="boolVariable ? 'border: 1px solid orange;' : 'border: none;'"
  />
</template>

to set the style prop to 'border: 1px solid orange;' if boolVariable is true and 'border: none;' otherwise.

Conclusion

To add condition in v-bind:style with Vue.js, we can set the style prop to the style string we want.

Categories
TypeScript Answers

How to fix Module not found: Error: Can’t resolve ‘crypto’ with TypeScript?

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Sometimes, we want to fix Module not found: Error: Can’t resolve ‘crypto’ with TypeScript.

In this article, we’ll look at how to fix Module not found: Error: Can’t resolve ‘crypto’ with TypeScript.

How to fix Module not found: Error: Can’t resolve ‘crypto’ with TypeScript?

To fix Module not found: Error: Can’t resolve ‘crypto’ with TypeScript, w e add a reference to the crypto library in tsconfig.json.

For instance, we write

{
  //...
  "compilerOptions": {
    "baseUrl": "./",
    "paths": {
      "crypto": ["node_modules/crypto-js"]
    }
  }
  //...
}

to set the path to the crypto module in the tsconfig.json file in the compilerOptions.paths JSON property.

Conclusion

To fix Module not found: Error: Can’t resolve ‘crypto’ with TypeScript, w e add a reference to the crypto library in tsconfig.json.

Categories
JavaScript Answers

How to make a simple image upload using JavaScript and HTML?

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Sometimes, we want to make a simple image upload using JavaScript and HTML.

In this article, we’ll look at how to make a simple image upload using JavaScript and HTML.

How to make a simple image upload using JavaScript and HTML?

To make a simple image upload using JavaScript and HTML, we can add a file input and img element.

And then we can get the selected file from the file input and show it in the img element.

For instance, we write

<input type="file" /> <br /><img id="myImg" src="#" />

to add the file input and img element.

Then we write

document.querySelector('input[type="file"]').addEventListener("change", (e) => {
  if (e.target?.files?.[0]) {
    const img = document.querySelector("img");
    img.onload = () => {
      URL.revokeObjectURL(img.src);
    };

    img.src = URL.createObjectURL(e.target?.files[0]);
  }
});

to select the file input with querySelector.

And then then we listen for its change event with addEventListener.

In the event listener, we get the file from e.target?.files?.[0].

Then we get the img element with querySelector.

We set the src property of the img element to the URL base64 string that we get by calling createObjectURL with the file object.

Then when the image is loaded, we call revokeObjectURL to clear the resources for creating the URL.

Conclusion

To make a simple image upload using JavaScript and HTML, we can add a file input and img element.

And then we can get the selected file from the file input and show it in the img element.

Categories
JavaScript Answers

How to open a new tab in the background with JavaScript?

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Sometimes, we want to open a new tab in the background with JavaScript.

In this article, we’ll look at how to open a new tab in the background with JavaScript.

How to open a new tab in the background with JavaScript?

To open a new tab in the background with JavaScript, we can simulate pressing ctrl-click on a link programmatically.

For instance, we write

const a = document.createElement("a");
a.href = "http://www.example.com/";
const evt = document.createEvent("MouseEvents");
evt.initMouseEvent(
  "click",
  true,
  true,
  window,
  0,
  0,
  0,
  0,
  0,
  true,
  false,
  false,
  false,
  0,
  null
);
a.dispatchEvent(evt);

to call createElement to create a link.

We set its href property to the URL we want to go to.

Then we call createEvent to create a mouse event.

And we call initMouseEvent to create a mouse event with the 10th argument set to true to enable pressing ctrl.

Next, we call dispatchEvent with evt to dispatch the mouse event to open the link in the background.

Conclusion

To open a new tab in the background with JavaScript, we can simulate pressing ctrl-click on a link programmatically.

Categories
TypeScript Answers

How to fix Error: *.default is not a constructor with TypeScript?

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Sometimes, we want to fix Error: *.default is not a constructor with TypeScript.

In this article, we’ll look at how to fix Error: *.default is not a constructor with TypeScript.

How to fix Error: *.default is not a constructor with TypeScript?

To fix Error: *.default is not a constructor with TypeScript, we should make sure we export a class as the default export.

For instance, we write

map_action_file.ts

export default class MapAction implements IMapAction {
  //...
}

to export the MapAction class in map_action_file.ts as a default export.

Then we import it by writing

import MapAction from "./map_action_file";

in another file in the same folder.

Conclusion

To fix Error: *.default is not a constructor with TypeScript, we should make sure we export a class as the default export.