Normalize title casing with reserved word replacements and add corresponding unit tests

Author: andrey-helldar

src/libs/words.ts

@@ -0,0 +1,12 @@
+export const reservedWords = [
+    "GitHub",
+    "BitBucket",
+    "GitLab",
+    "JSON",
+    "via",
+    "by",
+    "with",
+    "for",
+    "a",
+    "at",
+];

src/utils/strings.ts

@@ -1,13 +1,28 @@
+import { reservedWords } from "../libs/words";
+
+const normalizeWords = (value: string): string => {
+    for (const word of reservedWords) {
+        value = value.replace(new RegExp(`\\b${word}\\b`, "i"), word);
+    }
+
+    return value;
+};
+
 export const titleCase = (title: string | undefined) => {
     if (title === "" || title === undefined) {
         return "";
     }
 
-    return title
+    title = title
         .replace(/([A-Z])/g, "$1")
         .toLowerCase()
         .replace(/(^|\s|-|_)\S/g, (match: string) => match.toUpperCase())
-        .replace(/[-_]/g, " ");
+        .replace(/[-_]/g, " ")
+        .trim();
+
+    const normalized = normalizeWords(title);
+
+    return normalized.charAt(0).toUpperCase() + normalized.slice(1);
 };
 
 export const removeImages = (content: string): string =>

tests/unit/__snapshots__/strings.test.ts.snap

@@ -0,0 +1,141 @@
+// Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
+
+exports[`words 1`] = `
+[
+  "GitHub Bar",
+  "Foo GitHub Bar",
+  "Foo GitHub",
+  "GitHub Bar",
+  "Foo GitHub Bar",
+  "Foo GitHub",
+  "GitHub Bar",
+  "Foo GitHub Bar",
+  "Foo GitHub",
+]
+`;
+
+exports[`words 2`] = `
+[
+  "BitBucket Bar",
+  "Foo BitBucket Bar",
+  "Foo BitBucket",
+  "BitBucket Bar",
+  "Foo BitBucket Bar",
+  "Foo BitBucket",
+  "BitBucket Bar",
+  "Foo BitBucket Bar",
+  "Foo BitBucket",
+]
+`;
+
+exports[`words 3`] = `
+[
+  "GitLab Bar",
+  "Foo GitLab Bar",
+  "Foo GitLab",
+  "GitLab Bar",
+  "Foo GitLab Bar",
+  "Foo GitLab",
+  "GitLab Bar",
+  "Foo GitLab Bar",
+  "Foo GitLab",
+]
+`;
+
+exports[`words 4`] = `
+[
+  "JSON Bar",
+  "Foo JSON Bar",
+  "Foo JSON",
+  "JSON Bar",
+  "Foo JSON Bar",
+  "Foo JSON",
+  "JSON Bar",
+  "Foo JSON Bar",
+  "Foo JSON",
+]
+`;
+
+exports[`words 5`] = `
+[
+  "Via Bar",
+  "Foo via Bar",
+  "Foo via",
+  "Via Bar",
+  "Foo via Bar",
+  "Foo via",
+  "Via Bar",
+  "Foo via Bar",
+  "Foo via",
+]
+`;
+
+exports[`words 6`] = `
+[
+  "By Bar",
+  "Foo by Bar",
+  "Foo by",
+  "By Bar",
+  "Foo by Bar",
+  "Foo by",
+  "By Bar",
+  "Foo by Bar",
+  "Foo by",
+]
+`;
+
+exports[`words 7`] = `
+[
+  "With Bar",
+  "Foo with Bar",
+  "Foo with",
+  "With Bar",
+  "Foo with Bar",
+  "Foo with",
+  "With Bar",
+  "Foo with Bar",
+  "Foo with",
+]
+`;
+
+exports[`words 8`] = `
+[
+  "For Bar",
+  "Foo for Bar",
+  "Foo for",
+  "For Bar",
+  "Foo for Bar",
+  "Foo for",
+  "For Bar",
+  "Foo for Bar",
+  "Foo for",
+]
+`;
+
+exports[`words 9`] = `
+[
+  "A Bar",
+  "Foo a Bar",
+  "Foo a",
+  "A Bar",
+  "Foo a Bar",
+  "Foo a",
+  "A Bar",
+  "Foo a Bar",
+  "Foo a",
+]
+`;
+
+exports[`words 10`] = `
+[
+  "At Bar",
+  "Foo at Bar",
+  "Foo at",
+  "At Bar",
+  "Foo at Bar",
+  "Foo at",
+  "At Bar",
+  "Foo at Bar",
+  "Foo at",
+]
+`;

tests/unit/strings.test.ts

@@ -0,0 +1,26 @@
+import { reservedWords } from "../../src/libs/words";
+import { titleCase } from "../../src/utils/strings";
+
+test("words", () => {
+    for (const word of reservedWords) {
+        const lower = word.toLowerCase();
+        const upper = word.toUpperCase();
+
+        const items = [
+            // Base
+            `${word}_bar`,
+            `foo ${word}-bar`,
+            `foo ${word}_`,
+            // Lower
+            `${lower}_bar`,
+            `foo ${lower}-bar`,
+            `foo ${lower}_`,
+            // Upper
+            `${upper}_bar`,
+            `foo ${upper}-bar`,
+            `foo ${upper}_`,
+        ];
+
+        expect(items.map((item: string) => titleCase(item))).toMatchSnapshot();
+    }
+});