Duration cell formatting is stripped as color formatting

[ivankruchkoff]

This is:

- [X] a bug report

What is the expected behavior?

Cell value is:
12:34
Formatting is:
[mm]:ss

Per: https://support.office.com/en-us/article/number-format-codes-5026bbd6-04bc-48cd-bf33-80f18b4eae68 this is Elapsed time (minutes and seconds)

What is the current behavior?

[mm] is stripped from formatting here:

PhpSpreadsheet/src/PhpSpreadsheet/Style/NumberFormat.php

Line 641 in ce4b864

$format = preg_replace($color_regex, '', $format);

What are the steps to reproduce?

Please provide a Minimal, Complete, and Verifiable example of code that exhibits the issue without relying on an external Excel file or a web server:

<?php

require __DIR__ . '/vendor/autoload.php';

// Create new Spreadsheet object
$spreadsheet = new \PhpOffice\PhpSpreadsheet\Spreadsheet();

// add code that show the issue here...
use PhpOffice\PhpSpreadsheet\Style\NumberFormat;
$value = 0.0087268518518519;
$format = '[mm]:ss';
NumberFormat::toFormattedString( $value, $format )

Which versions of PhpSpreadsheet and PHP are affected?

1.2.0
PHP 7.0.26-2+ubuntu14.04.1+deb.sury.org+2

Sample File

bug-report.xlsx

$spreadsheet = $reader->load('bug-report.xlsx');
$spreadsheet->getActiveSheet()->getCell('A1')->getFormattedValue();

[PowerKiKi]

This is a duplicate of #342. Please try to contribute over there if this is important to you.