Category: JavaScript

Sometimes, we want to wait until an element is visible with Puppeteer and JavaScript.

In this article, we’ll look at how to wait until an element is visible with Puppeteer and JavaScript.

How to wait until an element is visible with Puppeteer and JavaScript?

To wait until an element is visible with Puppeteer and JavaScript, we can use the waitForFunction method.

For instance, we write

await page.waitForFunction(
  "document.querySelector('.btnNext') && document.querySelector('.btnNext').clientHeight !== 0"
);
await page.waitForFunction(
  "document.querySelector('.btnNext') && document.querySelector('.btnNext').style.visibility !== 'hidden'"
);

const btnNext = await page.$(".btnNext");
await btnNext.click();

to call waitForFunction with a string with expressions that checks if the element has a non-zero height and its visibility isn’t hidden.

After that, we get the element with $ and call click to click it.

Conclusion

To wait until an element is visible with Puppeteer and JavaScript, we can use the waitForFunction method.

Sometimes, we want to refresh leaflet map when map container is already initialized with JavaScript.

In this article, we’ll look at how to refresh leaflet map when map container is already initialized with JavaScript.

How to refresh leaflet map when map container is already initialized with JavaScript?

To refresh leaflet map when map container is already initialized with JavaScript, we call the off and remove methods before reloading the map.

For instance, we write

map.off();
map.remove();

to clear the map with off and remove before we reload the map to avoid the error.

Conclusion

To refresh leaflet map when map container is already initialized with JavaScript, we call the off and remove methods before reloading the map.

Sometimes, we want to create SVG graphics using JavaScript.

In this article, we’ll look at how to create SVG graphics using JavaScript.

How to create SVG graphics using JavaScript?

To create SVG graphics using JavaScript, we can use the createElementNS and setAttributeNS methods.

For instance, we write

const svgNs = "http://www.w3.org/2000/svg";
const shape = document.createElementNS(svgNs, "circle");
shape.setAttributeNS(null, "cx", 25);
shape.setAttributeNS(null, "cy", 25);
shape.setAttributeNS(null, "r", 20);
shape.setAttributeNS(null, "fill", "green");

to call document.createElementNS to create a circle element with the svgNs namespace.

Then we call shape.setAttributeNS to add the cx, cy, r and fill attributes to the shape circle element and set them to values in the 3rd argument.

Conclusion

To create SVG graphics using JavaScript, we can use the createElementNS and setAttributeNS methods.

Sometimes, we want to add nested JavaScript classes.

In this article, we’ll look at how to add nested JavaScript classes.

How to add nested JavaScript classes?

To add nested JavaScript classes, we can add a class as a static property of another class.

For instance, we write

class A {
  //...
}
A.B = class {
  //...
};

to add the A.B static property and assign it to a class.

Conclusion

To add nested JavaScript classes, we can add a class as a static property of another class.