Author: John Au-Yeung

Sometimes, we want to get all the elements of a particular form with JavaScript

In this article, we’ll look at how to get all the elements of a particular form with JavaScript.

How to get all the elements of a particular form with JavaScript?

To get all the elements of a particular form with JavaScript, we use the elements property.

For instance, we write

const formElements = document.getElementById("someFormId").elements;

to select the form element with getElementById.

Then we use the elements property to return a collection with all the elements in the form.

Elements returned includes input, select, textarea and button elements.

Conclusion

To get all the elements of a particular form with JavaScript, we use the elements property.

Sometimes, we want to remove all script tags from HTML with a JavaScript regular expression.

In this article, we’ll look at how to remove all script tags from HTML with a JavaScript regular expression.

How to removing all script tags from HTML with a JavaScript regular expression?

To remove all script tags from HTML with a JavaScript regular expression, we can use a regex that match the script tags and its contents.

For instance, we write

/<script\b[^<]*(?:(?!<\/script>)<[^<]*)*<\/script>/gi

to define a regex that matches the script tags and the contents inside.

We use g to find all matches.

And we use i to find matches in a case insensitive manner.

Conclusion

To remove all script tags from HTML with a JavaScript regular expression, we can use a regex that match the script tags and its contents.

Sometimes, we want to filter a JavaScript Map.

In this article, we’ll look at how to filter a JavaScript Map.

How to filter a JavaScript Map?

To filter a JavaScript Map, we convert it to an array.

For instance, we write

const map0 = new Map([
  ["a", 1],
  ["b", 2],
  ["c", 3],
]);

const map1 = new Map([...map0].filter(([k, v]) => v < 3));

console.info([...map1]);

to create a map with the Map constructor.

Then we convert it to an array with the spread operator.

And then we call filter with a function that checks if value v is less than 3.

We use the returned array to create another Map.

Conclusion

To filter a JavaScript Map, we convert it to an array.

Sometimes, we want to create an associative array in JavaScript literal notation.

In this article, we’ll look at how to create an associative array in JavaScript literal notation.

How to create an associative array in JavaScript literal notation?

To create an associative array in JavaScript literal notation, we can use maps.

For instance, we write

const arr = new Map([
  ["key1", "User"],
  ["key2", "Guest"],
  ["key3", "Admin"],
]);

const res = arr.get("key2");
console.log(res);

to create a map by calling the Map constructor with a nested array of key-value pair arrays.

Then we calk get to get the value with the key 'key2'.

So res is 'Guest'.

Conclusion

To create an associative array in JavaScript literal notation, we can use maps.

Sometimes, we want to fix JSON.stringify not working with normal JavaScript array.

In this article, we’ll look at how to fix JSON.stringify not working with normal JavaScript array.

How to fix JSON.stringify not working with normal JavaScript array?

To fix JSON.stringify not working with normal JavaScript array, we should make sure arrays have all numerical keys.

For instance, we write

const test = {};
test.a = "test";
test.b = [];
test.b.push("item");
test.b.push("item2");
test.b.push("item3");
const json = JSON.stringify(test);
console.log(json);

to create array properties a and b.

And we call push to push contents into it.

Then we call JSON.stringify to return the test object converted to a JSON string.

Conclusion

To fix JSON.stringify not working with normal JavaScript array, we should make sure arrays have all numerical keys.