How to get trimmed value via eloquent

What do you want to accomplish exactly?

class Article extends Model
{
    protected $table = 'articles';
    protected $fillable = ['content'];
}

$article = Article::find(1);
$sub = substr($article->content, 0, 100);

Laravel has a built-in string helper which achieves something similar to the native substr, but with added ellipsis (...):

str_limit($article->content, 20); // The quick brown fox...

https://laravel.com/docs/5.6/helpers#method-str-limit

Sorry I needed to clarify one thing. Here is my code:

$records = Article::where('title', 'like', '%'.$key.'%')->get();
return response()->json(['article' => $records]);

After an ajax call, corresponding records are found and returned. Instead of sending the whole content, I would like to send the first paragraph to utilize performance.

You would need to either iterate of the records in PHP, or more efficient would be to use a database function like MySQL's SUBSTRING() in your select query and limit by length rathe than paragraph:

Article::where('title', 'like', '%'.$key.'%')
    ->selectRaw('SUBSTRING(content, 1, 50) as snippet')
    ->get();

You can add extra data by chaining an addSelect('other', 'table', 'fields') to the query

You could go like this

$records = Article::where('title', 'like', '%'.$key.'%')->get()->toArray();

foreach ($records as &$record) {    
    $record['content'] = $this->getFirstParagraph($record['content']);
}

return response()->json(['article' => $records]);

public function getFirstParagraph($content)
{
    //Depends if you have HTML with p tag or plain text with dot
    $dotPos = strpos($content, '.');

    return $dotPos !== false
        ? substr($content, 0, $dotPos)
        : $content;
}

If you wanted, you could also define an accessor on the Article model which limits the string, and appends that property by default to JSON responses:

// Article.php

protected $appends = ['snippet'];

public function getSnippetAttribute()
{
    return str_limit($this->attributes['content'], 50);
}

This accessor approach would allow you to do more work to determine where the first paragraph ends.

You could mix @tykus solution with mine and add some extra code to achieve this

class Article extends Model
{
    ...

    protected $appends = ['paragraph'];

    protected $hidden = ['paragraph']; //by default we want content, not paragraph

    public function getParagraphAttribute()
    {
        //Depends if you have HTML with p tag or plain text with dot
        $dotPos = strpos($this->attributes['content'], '.');

        return $dotPos !== false
            ? substr($this->attributes['content'], 0, $dotPos)
            : $this->attributes['content'];
    }
}

$records = Article::where('title', 'like', '%'.$key.'%')
    ->get()
    ->makeVisible(['paragraph'])
    ->makeHidden(['content']) //to save resources
    ->toArray();

return response()->json(['article' => $records]);

After an ajax call, corresponding records are found and returned. Instead of sending the whole content, I would like to send the first paragraph to utilize performance.

@Joshuyo Create an accessor on your Article model to do exactly that:

class Article extends Model
{
    public function getFirstParagraphAttribute()
    {
        // Get first paragraph from $this->body
    }
}

I don’t know how you’re storing the body (plain text, HTML, Markdown etc), so I’ll leave it up to you on how to extract the first paragraph from your article’s body but when you’ve done so, you can call:

$firstParagraph = $article->first_paragraph;

Succinct and self-explanatory.