feat(guardDefined): guard value to not be undefined

Author: sciborrudnicki

packages/type/src/guard/lib/guard-defined.type.ts

@@ -0,0 +1,14 @@
+// Function.
+import { isDefined } from '../../is/lib/is-defined.func';
+// Type.
+import { Defined } from '../../type/defined.type';
+import { GuardDefined } from '../type/guard-defined.type';
+import { ResultCallback } from '../../type/result-callback.type';
+/**
+ * Checks if a generic type `value` is NOT an `undefined` type and is NOT equal to `undefined`.
+ * @param value A generic type `value` to check.
+ * @param callback An optional `ResultCallback` function to handle result before returns.
+ * @returns A `boolean` indicating whether or not the `value` is defined, if `undefined` then returns `never`.
+ */
+export const guardDefined: GuardDefined = <Type>(value: Type, callback?: ResultCallback): value is Defined<Type> =>
+  isDefined(value, callback);

packages/type/src/guard/type/guard-defined.type.ts

@@ -0,0 +1,3 @@
+import { Defined } from '../../type/defined.type';
+import { ResultCallback } from '../../type/result-callback.type';
+export type GuardDefined = <Type>(value: Type, callback?: ResultCallback) => value is Defined<Type>;

packages/type/src/type/defined.type.ts

@@ -0,0 +1 @@
+export type Defined<T> = T extends undefined ? never : T;