feat: add support for adding and overriding logs

src/formatters.ts

@@ -9,13 +9,14 @@ export const textFormatter: Formatter = (logParts) => {
 
 	const logMessageParts = [
 		capitalize(events.map(({ message }) => message).join(' and ')),
-		' because ',
+		events.length > 0 && ' because ',
 		explanations.map(({ message }) => message).join(' and '),
-		'.',
-		'\n',
-		'\n',
-		'Possible solutions:\n',
-		solutions.map(({ message }, solutionIndex) => `${solutionIndex + 1}) ${message}`)
+		explanations.length > 0 && '.',
+		solutions.length > 0 && explanations.length > 0 && '\n',
+		solutions.length > 0 && explanations.length > 0 && '\n',
+		solutions.length > 0 && 'Possible solutions:\n',
+		solutions.length > 0 &&
+			solutions.map(({ message }, solutionIndex) => `${solutionIndex + 1}) ${message}`).join('\n')
 	]
-	return logMessageParts.join('')
+	return logMessageParts.filter(Boolean).join('')
 }

src/index.ts

@@ -95,24 +95,44 @@ export function createHumanLogs<LogParts extends LogObject[]>(
 		// ...[params]: CombineParams<LogParts, LogNames> extends never ? [] : [CombineParams<LogParts, LogNames>]
 		params: CombineParams<LogParts, LogNames>
 	) {
-		const matchingParts = logs.filter(({ name }) => logParts.includes(name))
+		let localLogParts = [...logParts]
+		let localParams: CombineParams<LogParts, LogNames> = {
+			...params
+		}
 
-		// Then template all of the parts
-		const templatedParts = matchingParts.map((part) => {
-			return {
-				...part,
-				params: params as LogObject['params'],
-				message: replaceTemplateParams(part.message, params as LogObject['params'])
-			}
-		})
+		const getTemplatedParts = () =>
+			logs
+				.filter(({ name }) => localLogParts.includes(name))
+				.map((part) => ({
+					...part,
+					// params: params as LogObject['params'],
+					params: localParams,
+					message: replaceTemplateParams(part.message, localParams)
+				}))
 
 		return {
 			get parts() {
-				return templatedParts
+				return getTemplatedParts()
+			},
+			add<AddLogNames extends Array<LogParts[number]['name']>>(
+				logParts: AddLogNames,
+				params: CombineParams<LogParts, AddLogNames>
+			) {
+				localLogParts.push(...logParts)
+				localParams = { ...localParams, ...params }
+				return this
+			},
+			override<AddLogNames extends Array<LogParts[number]['name']>>(
+				logParts: AddLogNames,
+				params: CombineParams<LogParts, AddLogNames>
+			) {
+				localLogParts = logParts
+				localParams = { ...localParams, ...params }
+				return this
 			},
 			toString() {
 				const formatter = options.formatter ?? textFormatter
-				return formatter(templatedParts)
+				return formatter(getTemplatedParts())
 			}
 		}
 	}

test/logs.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest'
-import { mockErrors } from './setup'
+import { mockErrors } from './test-mocks'
 
 describe('formatters', () => {
 	it('default formatter', () => {
@@ -22,10 +22,70 @@ describe('formatters', () => {
 	})
 })
 
-describe.skip('chaining', () => {
-	const error = mockErrors(['fetch_posts_failed', 'missing_params', 'provide_fallback'], {
-		paramName: 'image',
-		paramType: 'Image',
-		postId: 'abcd-123'
+describe('chaining', () => {
+	it('add > no params', () => {
+		const error = mockErrors(['fetch_posts_failed', 'missing_params', 'provide_fallback'], {
+			paramName: 'image',
+			paramType: 'Image',
+			postId: 'abcd-123'
+		}).add(['check_statuspage'], {})
+
+		expect(error.toString()).toBe(
+			[
+				'Fetching posts failed because the Image `image` is missing for post with ID `abcd-123`, and no fallback was provided.',
+				'',
+				'Possible solutions:',
+				'1) add a fallback to your parameter definition like this: ',
+				'',
+				'url(`image`, { fallback: `https://useflytrap.com` })',
+				'2) you can check the status of our services on our status page'
+			].join('\n')
+		)
+	})
+
+	it('add > with params', () => {
+		const error = mockErrors(['fetch_posts_failed', 'missing_params', 'provide_fallback'], {
+			paramName: 'image',
+			paramType: 'Image',
+			postId: 'abcd-123'
+		}).add(['unsupported_blocktype'], {
+			blockType: 'Video'
+		})
+
+		expect(error.toString()).toBe(
+			[
+				'Fetching posts failed because the Image `image` is missing for post with ID `abcd-123`, and no fallback was provided and unsupported block type `Video` is included on this page.',
+				'',
+				'Possible solutions:',
+				'1) add a fallback to your parameter definition like this: ',
+				'',
+				'url(`image`, { fallback: `https://useflytrap.com` })'
+			].join('\n')
+		)
+	})
+
+	it('override > no params', () => {
+		const error = mockErrors(['fetch_posts_failed', 'missing_params', 'provide_fallback'], {
+			paramName: 'image',
+			paramType: 'Image',
+			postId: 'abcd-123'
+		}).override(['check_statuspage'], {})
+
+		expect(error.toString()).toBe(
+			[
+				'Possible solutions:',
+				'1) you can check the status of our services on our status page'
+			].join('\n')
+		)
+	})
+
+	it('override > with params', () => {
+		const error = mockErrors(['check_statuspage'], {}).override(['unsupported_blocktype'], {
+			blockType: 'Image'
+		})
+
+		expect(error.toString()).toBe(
+			['unsupported block type `Image` is included on this page.'].join('\n')
+		)
 	})
 })

test/setup.ts → test/test-mocks.ts

@@ -23,7 +23,7 @@ export const mockErrors = createHumanLogs([
 	),
 	explanation(
 		'unsupported_blocktype',
-		'unsupported block type `{blockType} is included on this page.`',
+		'unsupported block type `{blockType}` is included on this page',
 		{
 			params: { blockType: '' }
 		}

test/types.test.ts

@@ -1,5 +1,5 @@
-import { describe, expectTypeOf, it } from 'vitest'
-import { mockErrors } from './setup'
+import { describe, it } from 'vitest'
+import { mockErrors } from './test-mocks'
 
 describe('basic type tests', () => {
 	it('only valid keys', () => {