Category: JavaScript Answers

Sometimes, we want to return index value from filter method with JavaScript.

In this article, we’ll look at how to return index value from filter method with JavaScript.

How to return index value from filter method with JavaScript?

To return index value from filter method with JavaScript, we use the findIndex method.

For instance, we write

const data = [];
const fieldId = 5;
const index = data.findIndex((x) => x.id === fieldId);

to call data.findIndex with a callback to get the value with id set to fieldId.

The index of the first item in data that matches the condition will be returned.

Conclusion

To return index value from filter method with JavaScript, we use the findIndex method.

Sometimes, we want to convert ArrayBuffer to blob with JavaScript.

In this article, we’ll look at how to convert ArrayBuffer to blob with JavaScript.

How to convert ArrayBuffer to blob with JavaScript?

To convert ArrayBuffer to blob with JavaScript, we use the Blob constructor.

For instance, we write

const buffer = new ArrayBuffer(32);
const blob = new Blob([buffer]);

to create a Blob with the buffer by putting it in an array and using the array as the argument of Blob.

Conclusion

To convert ArrayBuffer to blob with JavaScript, we use the Blob constructor.

Sometimes, we want to fix JavaScript event window.onload not triggered.

In this article, we’ll look at how to fix JavaScript event window.onload not triggered.

How to fix JavaScript event window.onload not triggered?

To fix JavaScript event window.onload not triggered, we can use window.addEventListener.

For instance, we write

window.addEventListener("load", yourFunction);

to add yourFunction as the window load event listener into our page.

Conclusion

To fix JavaScript event window.onload not triggered, we can use window.addEventListener.

Sometimes, we want to get text between two rounded brackets with JavaScript.

In this article, we’ll look at how to get text between two rounded brackets with JavaScript.

How to get text between two rounded brackets with JavaScript?

To get text between two rounded brackets with JavaScript, we use the match method.

For instance, we write

const txt = "This is (my) simple text";
const re = /\((.*)\)/;
const [, match] = txt.match(re);

to use the /\((.*)\)/ regex to match the text between the parentheses.

Then we call txt.match with re to return the text between the parentheses by getting the 2nd entry from the array.

Conclusion

To get text between two rounded brackets with JavaScript, we use the match method.

Sometimes, we want to convert JSON string to array of JSON objects in JavaScript.

In this article, we’ll look at how to convert JSON string to array of JSON objects in JavaScript.

How to convert JSON string to array of JSON objects in JavaScript?

To convert JSON string to array of JSON objects in JavaScript, we use the JSON.parse method.

For instance, we write

const str = '[{"id":1,"name":"Test1"},{"id":2,"name":"Test2"}]';
const dataObj = JSON.parse(str);

to call JSON.parse with str to convert the string to an array of objects and return it.

Conclusion

To convert JSON string to array of JSON objects in JavaScript, we use the JSON.parse method.