feature: stripe-style prefixes

src/Ulid.php

@@ -11,14 +11,12 @@ class Ulid implements Stringable {
 	private string $randomString;
 
 	public function __construct(
-		float|int $init = null,
+		private ?string $prefix = null,
+		float|int $timestamp = null,
 		private int $length = self::DEFAULT_TOTAL_LENGTH,
 		private int $timestampLength = self::DEFAULT_TIMESTAMP_LENGTH,
 	) {
-		if(!is_null($init)) {
-			$timestamp = $init;
-		}
-		else {
+		if(is_null($timestamp)) {
 			$timestamp = microtime(true);
 		}
 
@@ -27,19 +25,31 @@ public function __construct(
 		$this->randomString = "";
 		for($i = 0; $i < $this->length - $this->timestampLength; $i++) {
 			$rnd = random_int(0, 31);
-			$this->randomString .= $this->base32(
-				$rnd
-			);
+			$this->randomString .= $this->base32($rnd);
 		}
 	}
 
 	public function __toString():string {
 		$timestampString = $this->getTimestampString();
 		$randomString = $this->getRandomString();
-		return implode("", [
+
+		$string = implode("", [
 			$timestampString,
 			$randomString,
 		]);
+
+		if($this->prefix) {
+			$string = implode("_", [
+				$this->prefix,
+				$string,
+			]);
+		}
+
+		return $string;
+	}
+
+	public function getPrefix():?string {
+		return $this->prefix;
 	}
 
 	public function getTimestamp():float {

test/phpunit/UlidTest.php

@@ -13,7 +13,7 @@ public function testGetTimestamp():void {
 
 	public function testGetTimestamp_setInConstructor():void {
 		$timestamp = (float)strtotime("5th April 1988");
-		$sut = new Ulid($timestamp);
+		$sut = new Ulid(timestamp: $timestamp);
 		self::assertSame($timestamp, $sut->getTimestamp());
 	}
 
@@ -22,15 +22,15 @@ public function testGetHexTimestamp_lexSorting():void {
 		for($year = 1970; $year < 2676; $year++) {
 			$timestamp = (float)strtotime("1st January $year");
 			$timestamp += rand(-1000, 1000) / 1000;
-			$sut = new Ulid($timestamp);
+			$sut = new Ulid(timestamp: $timestamp);
 			$hex = $sut->getTimestampString();
 			if($lastHex) {
 				self::assertGreaterThan($lastHex, $hex, $year);
 			}
 			$lastHex = $hex;
 		}
 
-		$sut = new Ulid(strtotime("5th April 1988"));
+		$sut = new Ulid(timestamp: strtotime("5th April 1988"));
 		self::assertLessThan($lastHex, $sut->getTimestampString());
 	}
 
@@ -41,7 +41,7 @@ public function testToString_unique():void {
 	public function testToString_length():void {
 		// Testing multiple times in case randomness causes different length strings.
 		for($i = 0; $i < 1_000; $i++) {
-			$sut = (string)(new Ulid(0));
+			$sut = (string)(new Ulid(timestamp: 0));
 			self::assertSame(Ulid::DEFAULT_TOTAL_LENGTH, strlen($sut));
 		}
 	}
@@ -79,4 +79,10 @@ public function testConstruct_setTimestampLength():void {
 			self::assertSame($tLength, strlen($tString));
 		}
 	}
+
+	public function testConstruct_prefix():void {
+		$sut = new Ulid("customer");
+		self::assertStringStartsWith("customer_", $sut);
+		self::assertGreaterThan(strlen("customer_") + 10, strlen($sut));
+	}
 }