Feature/xc 1539 (#21)

* add hash256 func

* add hash hasStr function

---------

Co-authored-by: tbal999 <[email protected]>

env.go

@@ -14,7 +14,6 @@ import (
 	"github.com/xiatechs/jsonata-go/jlib"
 	"github.com/xiatechs/jsonata-go/jparse"
 	"github.com/xiatechs/jsonata-go/jtypes"
-
 )
 
 type environment struct {
@@ -95,6 +94,12 @@ var baseEnv = initBaseEnv(map[string]Extension{
 		EvalContextHandler: defaultContextHandler,
 	},
 
+	"hashStr": {
+		Func:               jlib.Hash,
+		UndefinedHandler:   defaultUndefinedHandler,
+		EvalContextHandler: defaultContextHandler,
+	},
+
 	"objectsToDocument": {
 		Func:               jlib.ObjectsToDocument,
 		UndefinedHandler:   defaultUndefinedHandler,

jlib/hash.go

@@ -0,0 +1,37 @@
+package jlib
+
+import (
+	"crypto/md5"
+	"crypto/sha256"
+	"encoding/hex"
+	"strings"
+)
+
+// Hash a input string into a sha256 string
+// for deduplication purposes
+func Hash(hashType, input string) string {
+	switch strings.ToLower(hashType) {
+	case "sha256":
+		hasher := sha256.New()
+
+		hasher.Write([]byte(input))
+
+		hashedBytes := hasher.Sum(nil)
+
+		hashedString := hex.EncodeToString(hashedBytes)
+
+		return hashedString
+	case "md5":
+		hash := md5.Sum([]byte(input))
+
+		hashedString := hex.EncodeToString(hash[:])
+
+		return hashedString
+	}
+
+	hash := md5.Sum([]byte(input))
+
+	hashedString := hex.EncodeToString(hash[:])
+
+	return hashedString
+}