Add string utility functions: splitLines (#76)

Add feature splitLines for issue #29

Author: dom-baur

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- `splitLines` string utility function
+
 ### Changed
 
 - Moved `isValidSwissIbanNumber` and `isValidSwissSocialInsuranceNumber` to swissStandards

src/lib/string.spec.ts

@@ -1,4 +1,4 @@
-import { isNullOrEmpty, isNullOrWhitespace, capitalize, uncapitalize, truncate } from "./string";
+import { isNullOrEmpty, isNullOrWhitespace, capitalize, uncapitalize, truncate, splitLines } from "./string";
 
 describe("string tests", () => {
   test.each([
@@ -120,4 +120,41 @@ describe("string tests", () => {
   ])("truncate without suffix parameter", (value, maxLength, expected) => {
     expect(truncate(value, maxLength)).toBe(expected);
   });
+
+  test.each([
+    ["", false, false, []],
+    [null as unknown as string, false, false, []],
+    [undefined as unknown as string, false, false, []],
+    [" aaaa  \n\nbbbb  \n \ncccc", false, false, [" aaaa  ", "", "bbbb  ", " ", "cccc"]],
+    [" aaaa  \r\rbbbb  \r \rcccc", false, false, [" aaaa  ", "", "bbbb  ", " ", "cccc"]],
+    [" aaaa  \r\rbbbb  \n \r\ncccc", false, false, [" aaaa  ", "", "bbbb  ", " ", "cccc"]],
+    [" aaaa  \r\n\r\nbbbb  \r\n \r\ncccc", false, false, [" aaaa  ", "", "bbbb  ", " ", "cccc"]],
+
+    [" aaaa  \n\nbbbb  \n \ncccc", true, false, [" aaaa  ", "bbbb  ", " ", "cccc"]],
+    [" aaaa  \r\rbbbb  \r \rcccc", true, false, [" aaaa  ", "bbbb  ", " ", "cccc"]],
+    [" aaaa  \r\rbbbb  \n \r\ncccc", true, false, [" aaaa  ", "bbbb  ", " ", "cccc"]],
+    [" aaaa  \r\n\r\nbbbb  \r\n \r\ncccc", true, false, [" aaaa  ", "bbbb  ", " ", "cccc"]],
+
+    [" aaaa  \n\nbbbb  \n \ncccc", false, true, ["aaaa", "", "bbbb", "", "cccc"]],
+    [" aaaa  \r\rbbbb  \r \rcccc", false, true, ["aaaa", "", "bbbb", "", "cccc"]],
+    [" aaaa  \r\rbbbb  \n \r\ncccc", false, true, ["aaaa", "", "bbbb", "", "cccc"]],
+    [" aaaa  \r\n\r\nbbbb  \r\n \r\ncccc", false, true, ["aaaa", "", "bbbb", "", "cccc"]],
+
+    [" aaaa  \n\nbbbb  \n \ncccc", true, true, ["aaaa", "bbbb", "cccc"]],
+    [" aaaa  \r\rbbbb  \r \rcccc", true, true, ["aaaa", "bbbb", "cccc"]],
+    [" aaaa  \r\rbbbb  \n \r\ncccc", true, true, ["aaaa", "bbbb", "cccc"]],
+  ])("splitLines with parameter removeEmptyEntries and trimEntries", (str, removeEmptyEntries, trimEntries, expected) => {
+    expect(splitLines(str, removeEmptyEntries, trimEntries)).toEqual(expected);
+  });
+
+  test.each([
+    ["", []],
+    [null as unknown as string, []],
+    [undefined as unknown as string, []],
+    [" aaaa  \n\nbbbb  \n \ncccc", [" aaaa  ", "", "bbbb  ", " ", "cccc"]],
+    [" aaaa  \r\rbbbb  \r \rcccc", [" aaaa  ", "", "bbbb  ", " ", "cccc"]],
+    [" aaaa  \r\n\nbbbb  \r\n \r\ncccc", [" aaaa  ", "", "bbbb  ", " ", "cccc"]],
+  ])("splitLines with just the string as a parameter", (str, expected) => {
+    expect(splitLines(str)).toEqual(expected);
+  });
 });

src/lib/string.ts

@@ -64,3 +64,28 @@ export function truncate(value: string | undefined, maxLength: number, suffix =
 
   return `${value.slice(0, maxLength)}${suffix}`;
 }
+
+/**
+ * Splits the string at line breaks
+ * @param str the string to split
+ * @param removeEmptyEntries the option to remove empty entries
+ * @param trimEntries the option to trim the entries
+ * @returns the individual lines as an array
+ */
+export function splitLines(str: string, removeEmptyEntries: boolean = false, trimEntries: boolean = false): string[] {
+  if (isNullOrEmpty(str)) {
+    return [];
+  }
+
+  let splitted = str.split(/\r\n|\r|\n/);
+
+  if (trimEntries) {
+    splitted = splitted.map((x) => x.trim());
+  }
+
+  if (removeEmptyEntries) {
+    splitted = splitted.filter((line) => line.length > 0);
+  }
+
+  return splitted;
+}