make it easier to simulate errors

Author: kentcdodds

exercises/03.advanced-tools/04.problem.errors/README.mdx

@@ -15,6 +15,11 @@ For this step:
 This will make your journaling app more robust and user-friendly, and help LLMs
 handle problems gracefully.
 
+<callout-info>
+	ℹ️ In this exercise, you can simulate an error by trying to submit a tag with
+	the word "error" in the name.
+</callout-info>
+
 Example error response:
 
 ```json

exercises/03.advanced-tools/04.problem.errors/src/db/index.ts

@@ -155,6 +155,9 @@ export class DB {
 	// Tag Methods
 	async createTag(tag: NewTag) {
 		const validatedTag = newTagSchema.parse(tag)
+		if (validatedTag.name.toLocaleLowerCase().includes('error')) {
+			throw new Error('Tag name cannot include the word "error"')
+		}
 		const stmt = this.#db.prepare(sql`
 			INSERT INTO tags (name, description)
 			VALUES (?, ?)

exercises/03.advanced-tools/04.solution.errors/src/db/index.ts

@@ -155,6 +155,9 @@ export class DB {
 	// Tag Methods
 	async createTag(tag: NewTag) {
 		const validatedTag = newTagSchema.parse(tag)
+		if (validatedTag.name.toLocaleLowerCase().includes('error')) {
+			throw new Error('Tag name cannot include the word "error"')
+		}
 		const stmt = this.#db.prepare(sql`
 			INSERT INTO tags (name, description)
 			VALUES (?, ?)