Category: JavaScript

Sometimes, we want to convert returned JSON object properties to lower first camelCase with JavaScript.

In this article, we’ll look at how to convert returned JSON object properties to lower first camelCase with JavaScript.

How to convert returned JSON object properties to lower first camelCase with JavaScript?

To convert returned JSON object properties to lower first camelCase with JavaScript, we can use the Lodash mapKeys and camelCase functions.

For instance, we write

_.mapKeys(obj, (v, k) => _.camelCase(k));

to call mapKeys with obj and a callback that calls camelCase on key k to convert the keys in obj to camel case.

Conclusion

To convert returned JSON object properties to lower first camelCase with JavaScript, we can use the Lodash mapKeys and camelCase functions.

Sometimes, we want to convert all elements in an array to integer in JavaScript.

In this article, we’ll look at how to convert all elements in an array to integer in JavaScript.

How to convert all elements in an array to integer in JavaScript?

To convert all elements in an array to integer in JavaScript, w ecan use the array map method.

For instance, we write

const arrayOfNumbers = arrayOfStrings.map(Number);

to call arrayOfStrings.map with Number to return an array with the entries in arrayOfStrings converted to numbers.

Conclusion

To convert all elements in an array to integer in JavaScript, w ecan use the array map method.

Sometimes, we want to make the browser wait to display the page until it’s fully loaded with JavaScript.

In this article, we’ll look at how to make the browser wait to display the page until it’s fully loaded with JavaScript.

How to make the browser wait to display the page until it’s fully loaded with JavaScript?

To make the browser wait to display the page until it’s fully loaded with JavaScript, we run our code in the window.onload method.

For instance, we write

body {
  opacity: 0;
}

to set the body element to have opacity 0 initially.

Then we write

window.onload = () => {
  setTimeout(() => {
    document.body.style.opacity = "100";
  }, 500);
};

to set window.onload to a function that calls setTimeout with a callback that sets the body’s opacity to 100 after 500 milliseconds.

Conclusion

To make the browser wait to display the page until it’s fully loaded with JavaScript, we run our code in the window.onload method.

Sometimes, we want to pipe the same readable stream into multiple writable targets with Node.js and JavaScript.

In this article, we’ll look at how to pipe the same readable stream into multiple writable targets with Node.js and JavaScript.

How to pipe the same readable stream into multiple writable targets with Node.js and JavaScript?

To pipe the same readable stream into multiple writable targets with Node.js and JavaScript, we can use the PassThrough object.

For instance, we write

const spawn = require("child_process").spawn;
const PassThrough = require("stream").PassThrough;

const a = spawn("echo", ["hi user"]);
const b = new PassThrough();
const c = new PassThrough();

a.stdout.pipe(b);
a.stdout.pipe(c);

let count = 0;
b.on("data", (chunk) => {
  count += chunk.length;
});
b.on("end", () => {
  console.log(count);
  c.pipe(process.stdout);
});

to create PassThrough objects b and c.

Then we call a.stdout.pipe with them to pipe them to b and c.

Next we listen for data events on b to get the chunks.

And then when the end event is triggered on b, we call c.pipe with process.stdout to pipe process.stdout to c.

Conclusion

To pipe the same readable stream into multiple writable targets with Node.js and JavaScript, we can use the PassThrough object.