Nullable type that may be Opt<T> or undefined,
+opposite of the typescript builtin NonNullable<T>
+ Press n or j to go to the next uncovered block, b, p or k for the previous block. +
+ ++ Press n or j to go to the next uncovered block, b, p or k for the previous block. +
+ +| 1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +13 +14 +15 +16 +17 +18 +19 +20 +21 +22 +23 +24 +25 +26 | + + + + + + + + + + + + + + + + + + + + + +1x +7x +7x + | /**
+ * Utility functions for filtering and type checking
+ *
+ * @module
+ */
+
+import { Nullable } from "@/type";
+
+/**
+ * Check if a value is not `null` and not `undefined`.
+ *
+ * @typeParam T - type of value to check
+ *
+ * @param value - to check
+ * @returns whether value is not `null` and not `undefined`
+ *
+ * @example
+ * const isString = isNonNullable<string>("hello"); // true
+ * const isNull = isNonNullable(null); // false
+ * const isUndefined = isNonNullable(undefined); // false
+ * const nonNullables: number[] = [1, 2, null, undefined].filter(isNonNullable); // [1, 2]
+ */
+export function isNonNullable<T>(value: Nullable<T>): value is NonNullable<T> {
+ return value != null;
+}
+ |
+ Press n or j to go to the next uncovered block, b, p or k for the previous block. +
+ ++ Press n or j to go to the next uncovered block, b, p or k for the previous block. +
+ +| 1 +2 +3 +4 +5 +6 +7 +8 +9 | 1x + + + + + + + + | /**
+ * TypeScript utilities
+ *
+ * @module ts-utils
+ */
+
+export { isNonNullable } from '@/filter';
+export type { Nullable, Opt } from '@/type';
+ |
+ Press n or j to go to the next uncovered block, b, p or k for the previous block. +
+ +| 1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +13 +14 +15 +16 +17 +18 +19 +20 +21 +22 +23 +24 +25 +26 +27 +28 +29 +30 | + + + + + + + + + + + + + + + + + + + + + + + + + + + + + | /** + * Utility types + * + * @module + */ + +/** + * Optional type that may be `T` or `null` + * + * @typeParam T - non-null type + * + * @example + * const optString: Opt<string> = "hello"; + * const optNull: Opt<string> = null; + */ +export type Opt<T> = T | null; + +/** + * Nullable type that may be `Opt<T>` or `undefined`, + * opposite of the typescript builtin `NonNullable<T>` + * + * @typeParam T - non-null type + * + * @example + * const nullableString: Nullable<string> = "hello"; + * const nullableNull: Nullable<string> = null; + * const nullableUndefined: Nullable<string> = undefined; + */ +export type Nullable<T> = Opt<T> | undefined; + |
+ Press n or j to go to the next uncovered block, b, p or k for the previous block. +
+ +| 1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +13 +14 +15 +16 +17 +18 +19 +20 +21 +22 +23 +24 +25 +26 +27 +28 +29 | 1x + + + + + +1x + +1x + +1x + +1x +1x +1x +1x +1x +1x +3x +1x + +1x +1x +1x +1x +2x +1x +1x + | /**
+ * Unit tests for "@/filter" module
+ *
+ * @module
+ */
+
+import { describe } from 'node:test';
+
+import { expect, test } from 'vitest'
+
+import { isNonNullable } from '@';
+
+void describe('isNonNullable', () => {
+ test.each([
+ ["hello", true],
+ [null, false],
+ [undefined, false],
+ ])('isNonNullable(%o) -> %o', (value, expected) => {
+ expect(isNonNullable(value)).toBe(expected);
+ });
+
+ test.each([
+ [[], []],
+ [["hello", null, "there", undefined], ["hello", "there"]],
+ ])('%o.filter(isNonNullable) -> %o', (value, expected) => {
+ expect(value.filter(isNonNullable)).toStrictEqual(expected);
+ })
+})
+ |
+ Press n or j to go to the next uncovered block, b, p or k for the previous block. +
+ +| File | ++ | Statements | ++ | Branches | ++ | Functions | ++ | Lines | ++ |
|---|---|---|---|---|---|---|---|---|---|
| filter.test.ts | +
+
+ |
+ 100% | +19/19 | +100% | +3/3 | +100% | +0/0 | +100% | +19/19 | +
Check if a value is not
+nulland notundefined.