goquery filter doesn't return expected result

Question

magical internet,

I am trying to filter elements from an html string using "github.com/PuerkitoBio/goquery". Unfortunately, the filter function does not return the expected result. I would have expected to get back a list of all articles but instead, ... nothing.

package main

import (
    "fmt"
    "os"
    "strings"

    "github.com/PuerkitoBio/goquery"
)

var html = `
<section>
    <article>
        <h1>Article 1</h1>
        <p>Text for article #1</p>
    </article>
    <article>
        <h1>Article 2</h1>
        <p>Text for article #2</p>
    </article>
</section>
`

func main() {

    qHtml, err := goquery.NewDocumentFromReader(strings.NewReader(html))
    if err != nil {
        panic(err)
    }

    articles := qHtml.Filter(`article`)

    fmt.Println(articles.Nodes)
    goquery.Render(os.Stdout, articles)
}

Answer 1

You're trying to filter a selection that is empty.

From what I see you're trying to do in your question, you could simply replace the Filter with Find. So in your case it would be:

articles := qHtml.Find("article")

Once you have a selection containing elements, then you can use Filter. So, for example, to get the second article, you could do :

articles := qHtml.Find("article").Filter(":nth-child(2)")

To read more about Filter, check out these resources:

• goquery documentation
• jQuery Filter documentation
• jQuery Find documentation

PS: You can also combine it in single selector to Find specific article

articles := qHtml.Find("article:nth-child(2)")

Answer 2

As per doc

Filter reduces the set of matched elements to those that match the selector string. It returns a new Selection object for this subset of matching elements.

Since before Filter you are not matching anything that's why you got empty result since Filter got no matched elements.

You have to first match elements or get Selection set of nodes before you can apply Filter

To solve the issue instead of Filter you can use Find or FindMatcher

searchStr := `article`

articles := qHtml.Find(searchStr)

articles := qHtml.FindMatcher(goquery.Single(searchStr))