feat(logger): add Check for the logger (#34)

log.go

@@ -229,3 +229,10 @@ func Flush() error { return _globalL.Flush() }
 
 // Close implements io.Closer, and closes the current logfile of default logger.
 func Close() error { return _globalL.Close() }
+
+// Check returns a CheckedEntry if logging a message at the specified level
+// is enabled. It's a completely optional optimization; in high-performance
+// applications, Check can help avoid allocating a slice to hold fields.
+func Check(lvl Level, msg string) *CheckedEntry {
+	return _globalL.Check(lvl, msg)
+}

log_test.go

@@ -358,6 +358,25 @@ func TestStdInfoLogger(t *testing.T) {
 	})
 }
 
+func TestCheck(t *testing.T) {
+	r, w, _ := os.Pipe()
+	tmp := os.Stdout
+	defer func() {
+		os.Stdout = tmp
+	}()
+	os.Stdout = w
+	opts := NewOptions()
+	Configure(opts)
+
+	ce := Check(InfoLevel, "Hello, world!")
+	if ce != nil {
+		ce.Write(String("checked field", "checked field value"))
+	}
+	_ = w.Close()
+	stdout, _ := io.ReadAll(r)
+	assert.Contains(t, string(stdout), "Hello, world! {\"checked field\": \"checked field value\"}")
+}
+
 // fileWithLineNum return the file name and line number of the current file
 func fileWithLineNum() string {
 	for i := 4; i < 15; i++ {

logger.go

@@ -265,6 +265,10 @@ func (l *Logger) AtLevelf(level Level, msg string, args ...interface{}) {
 }
 
 // Sugared returns sugared logger.
+// SugaredLogger wraps the Logger to provide a more ergonomic, but slightly slower,
+// API. Sugaring a Logger is quite inexpensive, so it's reasonable for a
+// single application to use both Loggers and SugaredLoggers, converting
+// between them on the boundaries of performance-sensitive code.
 func (l *Logger) Sugared() *zap.SugaredLogger {
 	return l.sugared
 }
@@ -296,6 +300,13 @@ func (l *Logger) Close() error {
 	return nil
 }
 
+// Check returns a CheckedEntry if logging a message at the specified level
+// is enabled. It's a completely optional optimization; in high-performance
+// applications, Check can help avoid allocating a slice to hold fields.
+func (l *Logger) Check(lvl Level, msg string) *CheckedEntry {
+	return l.log.Check(lvl, msg)
+}
+
 func (l *Logger) EncodedFilename() string {
 	return l.encodedFilename
 }

types.go

@@ -11,6 +11,9 @@ type Field = zapcore.Field
 // Level is an alias for the zapcore.Level.
 type Level = zapcore.Level
 
+// CheckedEntry is an alias for the zapcore.CheckedEntry.
+type CheckedEntry = zapcore.CheckedEntry
+
 // TimeEncoder is an alias for the zapcore.TimeEncoder.
 type TimeEncoder = zapcore.TimeEncoder