src/Str.php
public function leftTrim(string $mask = null): self
    {
        return new self(
            $mask === null ? \ltrim((string) $this) : \ltrim((string) $this, $mask),
            $this->encoding
        );
    }
public function leftTrim(string $mask = null): self
    {
        return new self(
            $mask === null ? \ltrim((string) $this) : \ltrim((string) $this, $mask),
            $this->encoding
        );
    }
public function leftTrim ( string $ mask = null ) : self { return new self ( $ mask === null ? \ ltrim ( ( string ) $ this ) : \ ltrim ( ( string ) $ this , $ mask ) , $ this -> encoding ) ; }
Trim the left side of the string

@param string $mask

@return self
Trim the left side of the string