Category: JavaScript

Sometimes, we want to update record, and return result with Sequelize and JavaScript.

In this article, we’ll look at how to update record, and return result with Sequelize and JavaScript.

How to update record, and return result with Sequelize and JavaScript?

To update record, and return result with Sequelize and JavaScript, we can use the db.connections.update method.

For instance, we write

const result = await db.connections.update(
  {
    user: data.username,
    chatroomID: data.chatroomID,
  },
  {
    where: { socketID: socket.id },
    returning: true,
    plain: true,
  }
);

to call db.connection.update to update the user and chatroomID values.

We set returning to true to return the updated entry as an object with the promise returned by update.

Conclusion

To update record, and return result with Sequelize and JavaScript, we can use the db.connections.update method.

Sometimes, we want to create SVG elements dynamically with JavaScript inside HTML.

In this article, we’ll look at how to create SVG elements dynamically with JavaScript inside HTML.

How to create SVG elements dynamically with JavaScript inside HTML?

To create SVG elements dynamically with JavaScript inside HTML, we use the document.createElementNS method.

For instance, we write

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

to call the document.createElementNS method to create an svg element with the namespace for svg.

Conclusion

To create SVG elements dynamically with JavaScript inside HTML, we use the document.createElementNS method.

Sometimes, we want to pick element inside iframe using document.getElementById with JavaScript.

In this article, we’ll look at how to pick element inside iframe using document.getElementById with JavaScript.

How to pick element inside iframe using document.getElementById with JavaScript?

To pick element inside iframe using document.getElementById with JavaScript, we can use the contentWindow property.

For instance, we write

const el = document
  .getElementById("myframe1")
  .contentWindow.document.getElementById("x");

to select the iframe with getElementById.

Then we use contentWindow.document.getElementById to select the element with ID x in the iframe.

Conclusion

To pick element inside iframe using document.getElementById with JavaScript, we can use the contentWindow property.

Sometimes, we want to clear spy programmatically in Jasmine and JavaScript.

In this article, we’ll look at how to clear spy programmatically in Jasmine and JavaScript.

How to clear spy programmatically in Jasmine and JavaScript?

To clear spy programmatically in Jasmine and JavaScript, we can just change the spy.

For instance, we write

let spyObj;
beforeEach(() => {
  spyObj = spyOn(obj, "methodName").and.callFake((params) => {});
});

it("should do the declared spy behavior", () => {
  // ...
});

it("should do what it used to do", () => {
  spyObj.and.callThrough();
});

it("should do something differently", () => {
  spyObj.and.returnValue("new value");
});

to create the spyObj object with spyOn.

Then we write spyObj.and.callThrough(); to call obj.methodName in the first test.

In the 2nd test, we call spyObj.and.returnValue to return a new mocked value for obj.methodName.

The existing spy will be cleared after each test.

Conclusion

To clear spy programmatically in Jasmine and JavaScript, we can just change the spy.

Sometimes, we want to check if element is a div with JavaScript.

In this article, we’ll look at how to check if element is a div with JavaScript.

How to check if element is a div with JavaScript?

To check if element is a div with JavaScript, we can check the tagName property of the element.

For instance, we write

const myElement = document.getElementById("myElementId");

if (myElement.tagName === "DIV") {
  alert("is a div");
} else {
  alert("is not a div");
}

to select the element with getElementById.

Then we check if the myElement.tagName property returns 'DIV'.

If it is, then myElement is a div.

Conclusion

To check if element is a div with JavaScript, we can check the tagName property of the element.