Category: JavaScript

Sometimes, we want to test that a value is greater than or equal to in Jasmine and JavaScript.

In this article, we’ll look at how to test that a value is greater than or equal to in Jasmine and JavaScript.

How to test that a value is greater than or equal to in Jasmine and JavaScript?

To test that a value is greater than or equal to in Jasmine and JavaScript, we can use an expression that has the comparison operator.

For instance, we write

describe("percent", function () {
  it("should be a decimal", () => {
    const percent = insights.percent;

    expect(percent >= 0).toBeTruthy();
    expect(percent).toBeLessThan(1);
  });
});

to check that percent >= 0 is truthy to check that percent is bigger than or equal to 0.

Conclusion

To test that a value is greater than or equal to in Jasmine and JavaScript, we can use an expression that has the comparison operator.

Sometimes, we want to stub a class method with Sinon.js and JavaScript.

In this article, we’ll look at how to stub a class method with Sinon.js and JavaScript.

How to stub a class method with Sinon.js and JavaScript?

To stub a class method with Sinon.js and JavaScript, we can call the sinon.stub method.

For instance, we write

sinon.stub(YourClass.prototype, "myMethod").callsFake(() => {
  return {};
});

to stub the myMethod instance method in the YourClass class.

We call callsFake with a callback that returns the value we want for the fake method.

Likewise, we stub a static method with

sinon.stub(YourClass, "myStaticMethod").callsFake(() => {
  return {};
});

We call stub to stub the YouClass.myStaticMethod static method.

Conclusion

To stub a class method with Sinon.js and JavaScript, we can call the sinon.stub method.

Sometimes, we want to set multiple attributes for an element at once with JavaScript.

In this article, we’ll look at how to set multiple attributes for an element at once with JavaScript.

How to set multiple attributes for an element at once with JavaScript?

To set multiple attributes for an element at once with JavaScript, we can call the element’s setAttribute method.

For instance, we write

const setAttributes = (el, attrs) => {
  for (const [key, val] of Object.entries(attrs)) {
    el.setAttribute(key, val);
  }
};

const attrs = {
  src: "http://example.com/something.jpeg",
  height: "100%",
  //...
};
setAttributes(elem, attrs);

to define the setAttributes function.

In it, we use a for-of loop to loop through each property that we get from Object.entries.

In the loop, we call el.setAttribute with key and val to set attribute with name key to val.

Then we call setAttributes with the elem element and the attrs object with the attributes we want to set.

Conclusion

To set multiple attributes for an element at once with JavaScript, we can call the element’s setAttribute method.

Sometimes, we want to loop through localStorage in HTML5 and JavaScript.

In this article, we’ll look at how to loop through localStorage in HTML5 and JavaScript.

How to loop through localStorage in HTML5 and JavaScript?

To loop through localStorage in HTML5 and JavaScript,. we can use the Object.keys method to get the keys in localStorage.

For instance, we write

Object.keys(localStorage).forEach((key) => {
  console.log(localStorage.getItem(key));
});

to call Object.keys with localStorage to get an array of keys in localStorage.

Then we call forEach with a callback to get the value with the given key with getItem.

Conclusion

To loop through localStorage in HTML5 and JavaScript,. we can use the Object.keys method to get the keys in localStorage.