Added String.substring()

Tasks.todo

@@ -43,7 +43,7 @@ JSPHP:
       ☐ String.slice()
       ☐ String.split()
       ☐ String.startsWith()
-      ☐ String.substring()
+      ✔ String.substring() @done (06/01/2024 16:00:51)
       ☐ String.toLocaleLowerCase()
       ☐ String.toLocaleUpperCase()
       ✔ String.toLowerCase() @done (6/12/2023, 0:45:36)

jsphp.sublime-project

@@ -53,7 +53,10 @@
     {
       "name": "Coverage",
       "shell_cmd": "composer coverage -- --colors=never",
-      "quiet": true
+      "quiet": true,
     }
   ],
+  "debugger_configurations":
+  [
+	],
 }

phpunit.xml

@@ -3,7 +3,8 @@
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.4/phpunit.xsd"
   bootstrap="vendor/autoload.php"
-  cacheDirectory=".phpunit.cache">
+  cacheDirectory=".phpunit.cache"
+  displayDetailsOnTestsThatTriggerWarnings="true">
   <testsuites>
     <testsuite name="default">
       <directory>tests</directory>

src/JSString.php

@@ -64,6 +64,42 @@ function indexOf(?string $searchString = null, int $position = 0): int {
     return $position === false ? -1 : $position;
   }
 
+  /**
+   * Returns the substring at the specified location within a String object.
+   * @param int $start The zero-based index number indicating the beginning of the substring.
+   * @param ?int $end Zero-based index number indicating the end of the substring. The substring includes the characters up to, but not including, the character indicated by end.
+   * If end is omitted, the characters from start through the end of the original string are returned.
+   */
+  function substring(int $start, ?int $end = null): self {
+    $result = '';
+
+    if ($end === null) {
+      $end = $this->length;
+    }
+
+    if ($start < 0) {
+      $start = 0;
+    }
+
+    if ($end < 0) {
+      $end = 0;
+    }
+
+    if ($start > $end) {
+      return $this->substring($end, $start);
+    }
+
+    for ($i = $start; $i < $end; ++$i) {
+      if (!isset($this->value[$i])) {
+        break;
+      }
+
+      $result .= $this->value[$i];
+    }
+
+    return new self($result);
+  }
+
   /**
    * Returns the character at the specified index.
    * @param int|float $pos The zero-based index of the desired character.

tests/PHP/JSString/substringTest.php

@@ -0,0 +1,83 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\PHP\JSString;
+
+use JSString;
+use PHPUnit\Framework\TestCase;
+
+require_once __DIR__ . '/../../../vendor/autoload.php';
+
+final class substringTest extends TestCase {
+  function test_Demo_String_substring(): void {
+    $str = String('Mozilla');
+
+    self::assertEquals('oz', $str->substring(1, 3));
+    self::assertEquals('zilla', $str->substring(2));
+  }
+
+  function test_Using_substring(): void {
+    $anyString = String('Mozilla');
+
+    self::assertEquals('M', $anyString->substring(0, 1));
+    self::assertEquals('M', $anyString->substring(1, 0));
+    self::assertEquals('Mozill', $anyString->substring(0, 6));
+    self::assertEquals('lla', $anyString->substring(4));
+    self::assertEquals('lla', $anyString->substring(4, 7));
+    self::assertEquals('lla', $anyString->substring(7, 4));
+    self::assertEquals('Mozilla', $anyString->substring(0, 7));
+    self::assertEquals('Mozilla', $anyString->substring(0, 10));
+  }
+
+  function test_Using_substring_with_length_property(): void {
+    $text = String('Mozilla');
+
+    self::assertEquals('illa', $text->substring($text->length - 4));
+    self::assertEquals('zilla', $text->substring($text->length - 5));
+  }
+
+  function test_The_difference_between_substring_and_substr(): void {
+    $text = String('Mozilla');
+
+    self::assertEquals('zil', $text->substring(2, 5));
+    // self::assertEquals('zil', $text->substr(2, 3)); // TODO
+  }
+
+  function test_Differences_between_substring_and_slice(): void {
+    $text = String('Mozilla');
+
+    self::assertEquals('zil', $text->substring(5, 2));
+    // self::assertEquals("", $text->slice(5, 2)); // TODO
+
+    /* If either or both of the arguments are negative or NaN, the substring()
+    method treats them as if they were 0. */
+    self::assertEquals('Mo', $text->substring(-5, 2));
+    self::assertEquals('', $text->substring(-5, -2));
+
+    /* slice() also treats NaN arguments as 0, but when it is given negative
+    values it counts backwards from the end of the string to find the indexes. */
+    // self::assertEquals('', $text->slice(-5, 2)); // TODO
+    // self::assertEquals('zil', $text->slice(-5, -2)); // TODO
+  }
+
+  function test_Replacing_a_substring_within_a_string(): void {
+    // Replaces oldS with newS in the string fullS
+    $replaceString = function (JSString $oldS, string $newS, JSString $fullS): JSString {
+      for ($i = 0; $i < $fullS->length; ++$i) {
+        if ($fullS->substring($i, $i + $oldS->length) == $oldS) {
+          $fullS = String($fullS->substring(0, $i) . $newS . $fullS->substring($i + $oldS->length, $fullS->length));
+        }
+      }
+
+      return $fullS;
+    };
+
+    // $replaceStringBetterMethod = function (string $oldS, string $newS, JSString $fullS): JSString {
+    //   return $fullS->split($oldS)->join($newS); // TODO
+    // };
+
+    self::assertEquals('Brave New Web', $replaceString(String('World'), 'Web', String('Brave New World')));
+    // self::assertEquals('Brave New Web', $replaceStringBetterMethod('World', 'Web', String('Brave New World')));
+  }
+}