Use regular expressions to match id values

Question

I want to find all child nodes of the g node whose value is id and the attribute consists of:

a[number]-[one or more characters]

// example:
// - id="a1-a"
// - id="a1-b"
// - id="a1-abcd"
// - id="a10-f"
// - id="a0-z"
// - id="b1-a" // Illegal
// - id="a1-2" // Illegal

So I tried:

<code>const items = gElement.querySelectorAll(`[id^='a[0-9] -[a-zA-Z] ']`)
</code>

However, it doesn't work.

Answer 1

In your query selector, you are using a pattern ([0-9] ) that is not interpreted as a regular expression. Create a regular expression object from a string using the RegExp constructor:

const regex = new RegExp('^a[0-9]+-[a-zA-Z]+$');
const parentElement = document.querySelector('#parent-element');
const items = parentElement.querySelectorAll(`[id]`);
const children = Array.from(items).filter(item => regex.test(item.id));

console.log(children); 

<div id="parent-element">
  <p id="a1-a">Child 1</p>
  <p id="a1-b">Child 2</p>
  <p id="INVALID-1">Child 3</p>
  <p id="a10-f">Child 4</p>
  <p id="INVALID-2">Child 5</p>
  <p id="b1-a">Child 6</p>
  <p id="a1-2">Child 7</p>
</div>