Trim

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

Returns the given string with whitespace stripped from the beginning and end

namespace HH\Lib\Str;

function trim(
  string $string,
  ?string $char_mask = NULL,
): string;

If the optional character mask isn't provided, the following characters will be stripped: space, tab, newline, carriage return, NUL byte, vertical tab.

• To only strip from the left, see Str\trim_left().
• To only strip from the right, see Str\trim_right().

Guide

• String

Parameters

• string $string
• ?string $char_mask = NULL

Returns

• string

Examples

$result = Str\trim("example_string    ");
echo($result);
//result: "example_string"

$result = Str\trim("   example_string  ");
echo($result);
//result: "example_string"