Category: JavaScript Answers

Sometimes, we want to make canvas as wide and as high as parent with JavaScript.

In this article, we’ll look at how to make canvas as wide and as high as parent with JavaScript.

How to make canvas as wide and as high as parent with JavaScript?

To make canvas as wide and as high as parent with JavaScript, we can set the width and height.

For instance, we write

const canvas = document.querySelector("canvas");

const fitToContainer = (canvas) => {
  canvas.style.width = "100%";
  canvas.style.height = "100%";
  canvas.width = canvas.offsetWidth;
  canvas.height = canvas.offsetHeight;
};

fitToContainer(canvas);

to define the fitToContainer to set the width and height of the canvas to fit the parent with

canvas.style.width = "100%";
canvas.style.height = "100%";
canvas.width = canvas.offsetWidth;
canvas.height = canvas.offsetHeight;

Then we call fitToContainer with canvas to resize the canvas.

Conclusion

To make canvas as wide and as high as parent with JavaScript, we can set the width and height.

Sometimes, we want to getElementByClass instead of GetElementById with JavaScript.

In this article, we’ll look at how to getElementByClass instead of GetElementById with JavaScript.

How to getElementByClass instead of GetElementById with JavaScript?

To getElementByClass instead of GetElementById with JavaScript, we use the getElementsByClassName method.

For instance, we write

document.getElementsByClassName("classname")[0].style.display = "none";

to get the first element with class classname with

document.getElementsByClassName("classname")[0]

Then we set the style.display property of it to 'none' to set its display CSS style to none.

Conclusion

To getElementByClass instead of GetElementById with JavaScript, we use the getElementsByClassName method.

Sometimes, we want to fix using forEach on an array from getElementsByClassName results in “TypeError: undefined is not a function” error with JavaScript.

In this article, we’ll look at how to fix using forEach on an array from getElementsByClassName results in “TypeError: undefined is not a function” error with JavaScript.

How to fix using forEach on an array from getElementsByClassName results in “TypeError: undefined is not a function” error with JavaScript?

To fix using forEach on an array from getElementsByClassName results in “TypeError: undefined is not a function” error with JavaScript, we can use the spread operator to convert the node list returned by getElementsByClassName to an array.

For instance, we write

[...document.getElementsByClassName("myClass")].forEach((v) => {
  //...
});

to get the elements with class myClass with getElementsByClassName.

Then we spread the entries in the node list returned by getElementsByClassName into an array.

Next, we call forEach with a callback to loop through each element.

Conclusion

To fix using forEach on an array from getElementsByClassName results in “TypeError: undefined is not a function” error with JavaScript, we can use the spread operator to convert the node list returned by getElementsByClassName to an array.

Sometimes, we want to create Mongoose schema with an array of object IDs with JavaScript.

In this article, we’ll look at how to create Mongoose schema with an array of object IDs with JavaScript.

How to create Mongoose schema with an array of object IDs with JavaScript?

To create Mongoose schema with an array of object IDs with JavaScript, we can set schema property to an array of objects that specifies that the field is an array of object IDs.

For instance, we write

const userSchema = mongoose.Schema({
  email: { type: String, required: true, unique: true },
  password: { type: String, required: true },
  name: {
    first: { type: String, required: true, trim: true },
    last: { type: String, required: true, trim: true },
  },
  phone: Number,
  lists: [listSchema],
  friends: [{ type: ObjectId, ref: "User" }],
  accessToken: { type: String },
});

exports.User = mongoose.model("User", userSchema);

to create the userSchema that has the friends field that holds an array of object IDs by setting friends to [{ type: ObjectId, ref: "User" }].

We specifies that each friends entry references the object ID of a User.

Conclusion

To create Mongoose schema with an array of object IDs with JavaScript, we can set schema property to an array of objects that specifies that the field is an array of object IDs.

Sometimes, we want to reload CSS without reloading the page with JavaScript.

In this article, we’ll look at how to reload CSS without reloading the page with JavaScript.

How to reload CSS without reloading the page with JavaScript?

To reload CSS without reloading the page with JavaScript, we can loop through the link elements and update their href attribute values.

For instance, we write

const reloadCss = () => {
  const links = document.getElementsByTagName("link");
  for (const link of links) {
    if (link.rel === "stylesheet") {
      link.href += "";
    }
  }
};

to define the reloadCss function.

In it, we get all the link elements with getElementsByTagName.

Then we loop through the links with a for-of loop.

In it, we check if the rel attribute of each link is 'stylesheet' with

link.rel === "stylesheet"

If it is, then we update the href attribute with

link.href += ""

to reload the CSS referenced by the link element.

Conclusion

To reload CSS without reloading the page with JavaScript, we can loop through the link elements and update their href attribute values.