added delete snippet, update snippet, create snippet and save on snippet change

browser/main/lib/dataApi/updateSnippet.js

@@ -0,0 +1,34 @@
+import fs from 'fs'
+import consts from 'browser/lib/consts'
+
+function updateSnippet (snippet) {
+  return new Promise((resolve, reject) => {
+    let snippets = JSON.parse(fs.readFileSync(consts.SNIPPET_FILE, 'utf-8'))
+
+    for (let i = 0; i < snippets.length; i++) {
+      let currentSnippet = snippets[i]
+
+      if (currentSnippet.id === snippet.id) {
+        if (
+          currentSnippet.name === snippet.name &&
+          currentSnippet.prefix === snippet.prefix &&
+          currentSnippet.content === snippet.content
+        ) {
+          // if everything is the same then don't write to disk
+          resolve(snippets)
+        } else {
+          currentSnippet.name = snippet.name
+          currentSnippet.prefix = snippet.prefix
+          currentSnippet.content = snippet.content
+          
+          fs.writeFile(consts.SNIPPET_FILE, JSON.stringify(snippets, null, 4), (err) => {
+            if (err) reject(err)
+            resolve(snippets)
+          })
+        }
+      }
+    }
+  })
+}
+
+module.exports = updateSnippet