feat: add string utils

src/index.ts

@@ -3,3 +3,4 @@ export * from './date';
 export * from './pluralize';
 export * from './predicates';
 export * from './round';
+export * from './string';

src/string.test.ts

@@ -0,0 +1,32 @@
+import {firstLine, includesIgnoreCase} from './string';
+
+describe('includesIgnoreCase', () => {
+  it('finds exact match', () => {
+    expect(includesIgnoreCase('find me', 'search and find me')).toBeTruthy();
+    expect(includesIgnoreCase('find it', 'search and find me again')).toBeFalsy();
+    expect(includesIgnoreCase('fist part', 'first part')).toBeFalsy();
+  });
+
+  it('finds no match', () => {
+    expect(includesIgnoreCase('find it', 'search and find me again')).toBeFalsy();
+  });
+
+  it('finds match', () => {
+    expect(includesIgnoreCase('find MÖ', 'search and find mö')).toBeTruthy();
+    expect(includesIgnoreCase('find mö', 'search and find MÖ')).toBeTruthy();
+  });
+});
+
+describe('firstLine', () => {
+  it('gets the first line of a multiline string', () => {
+    expect(firstLine('foo\nbar')).toEqual('foo');
+  });
+
+  it('gets the first line of a one line string', () => {
+    expect(firstLine('foo')).toEqual('foo');
+  });
+
+  it('returns an empty string for empty strings', () => {
+    expect(firstLine('')).toEqual('');
+  });
+});

src/string.ts

@@ -0,0 +1,14 @@
+export function includesIgnoreCase(
+  needle: string,
+  haystack: string | Array<string>,
+): boolean {
+  if (haystack instanceof Array) {
+    return haystack.some((hay) => includesIgnoreCase(needle, hay));
+  }
+
+  return haystack.toLowerCase().includes(needle.toLowerCase());
+}
+
+export function firstLine(multilineText: string): string {
+  return multilineText.split('\n', 1)[0];
+}