feat(grease): createGreaser

Signed-off-by: Lexus Drumgold <unicornware@flexdevelopment.llc>

src/__tests__/grease.create.spec.ts

@@ -0,0 +1,13 @@
+/**
+ * @file Unit Tests - createGreaser
+ * @module grease/tests/unit/createGreaser
+ */
+
+import testSubject from '../grease.create'
+import GreaseService from '../grease.service'
+
+describe('unit:createGreaser', () => {
+  it('should return grease runner instance', async () => {
+    expect(await testSubject()).to.be.instanceof(GreaseService)
+  })
+})

src/grease.create.ts

@@ -0,0 +1,41 @@
+/**
+ * @file createGreaser
+ * @module grease/create
+ */
+
+import { LoggerService, UserLogLevel } from '#src/log'
+import type { INestApplicationContext as App } from '@nestjs/common'
+import { NestFactory } from '@nestjs/core'
+import GreaseModule from './grease.module'
+import GreaseService from './grease.service'
+
+/**
+ * Create a greaser.
+ *
+ * @see {@linkcode GreaseService}
+ *
+ * @async
+ *
+ * @return {Promise<GreaseService>} Grease runner instance
+ */
+const createGreaser = async (): Promise<GreaseService> => {
+  /**
+   * NestJS application context.
+   *
+   * @const {App} app
+   */
+  const app: App = await NestFactory.createApplicationContext(GreaseModule, {
+    abortOnError: false,
+    autoFlushLogs: false,
+    bufferLogs: true
+  })
+
+  // use custom logger
+  app.useLogger(app.get(LoggerService).withTag('nest'))
+  app.useLogger([UserLogLevel.WARN])
+  app.flushLogs()
+
+  return (await app.init()).get(GreaseService)
+}
+
+export default createGreaser

src/index.ts

@@ -5,6 +5,7 @@
 
 export * from './decorators'
 export * from './enums'
+export { default as createGreaser } from './grease.create'
 export { default as GreaseModule } from './grease.module'
 export { default as GreaseService } from './grease.service'
 export type * from './interfaces'

src/subdomains/log/providers/__tests__/logger.service.spec.ts

@@ -87,6 +87,21 @@ describe('unit:log/providers/LoggerService', () => {
     })
   })
 
+  describe('#setLogLevels', () => {
+    it('should return this log level', () => {
+      // Arrange
+      const cases: [keyof typeof LogLevel, UserLogLevel[]][] = [
+        ['LOG', []],
+        ['WARN', [UserLogLevel.ERROR, UserLogLevel.FATAL, UserLogLevel.WARN]]
+      ]
+
+      // Act + Expect
+      cases.forEach(([key, levels]) => {
+        expect(new TestSubject().setLogLevels(levels)).to.equal(LogLevel[key])
+      })
+    })
+  })
+
   describe('#sync', () => {
     let subject: TestSubject
 

src/subdomains/log/providers/logger.service.ts

@@ -11,6 +11,7 @@ import type { Reporter } from '#src/log/reporters'
 import type { Colors } from '#src/log/types'
 import type { GlobalOptions } from '#src/options'
 import {
+  at,
   define,
   fallback,
   ifelse,
@@ -24,6 +25,7 @@ import {
   omit,
   select,
   set,
+  sort,
   template,
   uppercase,
   values,
@@ -272,6 +274,24 @@ class LoggerService implements ILogger {
     })
   }
 
+  /**
+   * Set `this` log level to the highest level in the given log level array.
+   *
+   * @public
+   *
+   * @param {OrLowercase<UserLogLevel>[]} levels - Log levels
+   * @return {LogLevel} `this` log level
+   */
+  public setLogLevels(levels: OrLowercase<UserLogLevel>[]): LogLevel {
+    if (levels.length) {
+      this.level = at(sort(levels, (level1, level2) => {
+        return LogLevel[uppercase(level2)] - LogLevel[uppercase(level1)]
+      }), 0)
+    }
+
+    return this.level
+  }
+
   /**
    * Write a `start` log.
    *