Added xOrNull methods.

Author: electricessence

README.md

@@ -182,6 +182,7 @@ sequence.first(predicate);
 sequence.last(predicate);
 sequence.singleOrDefault(defaultValue, predicate);
 sequence.firstOrUndefined(predicate);
+sequence.lastOrNull(predicate);
 ```
 
 A resolution is a transform that takes an `Iterable<T>` and returns `TResult`.

dist-esm/LinqExtendedBase.js

@@ -51,6 +51,12 @@ export default abstract class LinqExtendedBase<T, TLinq extends LinqExtendedBase
      * @return {T | undefined}
      */
     singleOrUndefined(predicate?: PredicateWithIndex<T>): T | undefined;
+    /**
+     * Returns the expected single element; otherwise undefined.
+     * @param {PredicateWithIndex<T>} [predicate]
+     * @return {T | null}
+     */
+    singleOrNull(predicate?: PredicateWithIndex<T>): T | null;
     /**
      * Returns the first element of the sequence.
      * @param {PredicateWithIndex<T>} [predicate]
@@ -70,6 +76,12 @@ export default abstract class LinqExtendedBase<T, TLinq extends LinqExtendedBase
      * @return {T | undefined}
      */
     firstOrUndefined(predicate?: PredicateWithIndex<T>): T | undefined;
+    /**
+     * Returns the first element of the sequence; otherwise undefined.
+     * @param {PredicateWithIndex<T>} [predicate]
+     * @return {T | null}
+     */
+    firstOrNull(predicate?: PredicateWithIndex<T>): T | null;
     /**
      * Returns the last element of the sequence.
      * @param {PredicateWithIndex<T>} [predicate]
@@ -89,4 +101,10 @@ export default abstract class LinqExtendedBase<T, TLinq extends LinqExtendedBase
      * @return {T | undefined}
      */
     lastOrUndefined(predicate?: PredicateWithIndex<T>): T | undefined;
+    /**
+     * Returns the last element of the sequence; otherwise null.
+     * @param {PredicateWithIndex<T>} [predicate]
+     * @return {T | null}
+     */
+    lastOrNull(predicate?: PredicateWithIndex<T>): T | null;
 }

dist-esm/LinqExtendedBase.js.map

@@ -91,6 +91,15 @@ export default abstract class LinqExtendedBase<T, TLinq extends LinqExtendedBase
 		return singleOrDefault<T, undefined>(undefined)(predicate ? this.where(predicate) : this.source);
 	}
 
+	/**
+	 * Returns the expected single element; otherwise undefined.
+	 * @param {PredicateWithIndex<T>} [predicate]
+	 * @return {T | null}
+	 */
+	singleOrNull(predicate?: PredicateWithIndex<T>): T | null {
+		return singleOrDefault<T, null>(null)(predicate ? this.where(predicate) : this.source);
+	}
+
 	/**
 	 * Returns the first element of the sequence.
 	 * @param {PredicateWithIndex<T>} [predicate]
@@ -119,6 +128,15 @@ export default abstract class LinqExtendedBase<T, TLinq extends LinqExtendedBase
 		return firstOrDefault<T, undefined>(undefined)(predicate ? this.where(predicate) : this.source);
 	}
 
+	/**
+	 * Returns the first element of the sequence; otherwise undefined.
+	 * @param {PredicateWithIndex<T>} [predicate]
+	 * @return {T | null}
+	 */
+	firstOrNull(predicate?: PredicateWithIndex<T>): T | null {
+		return firstOrDefault<T, null>(null)(predicate ? this.where(predicate) : this.source);
+	}
+
 	/**
 	 * Returns the last element of the sequence.
 	 * @param {PredicateWithIndex<T>} [predicate]
@@ -146,4 +164,13 @@ export default abstract class LinqExtendedBase<T, TLinq extends LinqExtendedBase
 	lastOrUndefined(predicate?: PredicateWithIndex<T>): T | undefined {
 		return lastOrDefault<T, undefined>(undefined)(predicate ? this.where(predicate) : this.source);
 	}
+
+	/**
+	 * Returns the last element of the sequence; otherwise null.
+	 * @param {PredicateWithIndex<T>} [predicate]
+	 * @return {T | null}
+	 */
+	lastOrNull(predicate?: PredicateWithIndex<T>): T | null {
+		return lastOrDefault<T, null>(null)(predicate ? this.where(predicate) : this.source);
+	}
 }